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    <link:label id="lab_us-gaap_DisclosureOfLongLivedAssetsHeldForSaleTextBlock_1FA7BB6CBB00F87876A9E60968BF2A3F_terseLabel_en-US" xlink:label="lab_us-gaap_DisclosureOfLongLivedAssetsHeldForSaleTextBlock_1FA7BB6CBB00F87876A9E60968BF2A3F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Components of assets held for sale</link:label>
    <link:label id="lab_us-gaap_DisclosureOfLongLivedAssetsHeldForSaleTextBlock_1FA7BB6CBB00F87876A9E60968BF2A3F_label_en-US" xlink:label="lab_us-gaap_DisclosureOfLongLivedAssetsHeldForSaleTextBlock_1FA7BB6CBB00F87876A9E60968BF2A3F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disclosure of Long Lived Assets Held-for-sale [Table Text Block]</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentTable_16D1129C2B71B8B54488BF5CEDF34F43_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable_16D1129C2B71B8B54488BF5CEDF34F43" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentTable_16D1129C2B71B8B54488BF5CEDF34F43_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentTable_16D1129C2B71B8B54488BF5CEDF34F43" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Long-term Debt Instruments [Table]</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentAxis_ADEDF6A0E95A741E02B4BF5CEDF34762_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis_ADEDF6A0E95A741E02B4BF5CEDF34762" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument [Axis]</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentAxis_ADEDF6A0E95A741E02B4BF5CEDF34762_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentAxis_ADEDF6A0E95A741E02B4BF5CEDF34762" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument [Axis]</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentNameDomain_73E929F8D5EE2425A986BF5CEDF3BFBE_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentNameDomain_73E929F8D5EE2425A986BF5CEDF3BFBE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument, Name [Domain]</link:label>
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    <link:label id="lab_us-gaap_SecuredDebtMember_E06009235CCF679BFF24BF5CEDF33C55_terseLabel_en-US" xlink:label="lab_us-gaap_SecuredDebtMember_E06009235CCF679BFF24BF5CEDF33C55" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage and Other Secured Loans:</link:label>
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    <link:label id="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241_terseLabel_en-US" xlink:label="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fixed rate mortgage loans</link:label>
    <link:label id="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241_label_en-US" xlink:label="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fixed Rate Secured Debt [Member]</link:label>
    <link:label id="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241_documentation_en-US" xlink:label="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">A collateralized debt obligation (backed by pledge, mortgage or other lien on the entity's assets) bearing fixed interest rates.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_FixedRateSecuredDebtMember" xlink:label="loc_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241" xlink:to="lab_ofc_FixedRateSecuredDebtMember_CB42A7ED1F0F9A5CA71ABF5CEDF31241" xlink:type="arc" />
    <link:label id="lab_ofc_FixedRateMortgageLoan2034Member_D495E9712142FCBEE7E3BF5CEDF366A7_terseLabel_en-US" xlink:label="lab_ofc_FixedRateMortgageLoan2034Member_D495E9712142FCBEE7E3BF5CEDF366A7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fixed rate mortgage loan maturing 2034</link:label>
    <link:label id="lab_ofc_FixedRateMortgageLoan2034Member_D495E9712142FCBEE7E3BF5CEDF366A7_label_en-US" xlink:label="lab_ofc_FixedRateMortgageLoan2034Member_D495E9712142FCBEE7E3BF5CEDF366A7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fixed Rate Mortgage Loan 2034 [Member]</link:label>
    <link:label id="lab_ofc_FixedRateMortgageLoan2034Member_D495E9712142FCBEE7E3BF5CEDF366A7_documentation_en-US" xlink:label="lab_ofc_FixedRateMortgageLoan2034Member_D495E9712142FCBEE7E3BF5CEDF366A7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the fixed-rate mortgage loan of the entity which matures in 2034, but may be repaid in March 2014 subject to certain conditions.</link:label>
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    <link:label id="lab_ofc_ConstructionLineOfCreditMember_D4CF6E6EAAE5C4D407CCBF5CEDF3B2E5_terseLabel_en-US" xlink:label="lab_ofc_ConstructionLineOfCreditMember_D4CF6E6EAAE5C4D407CCBF5CEDF3B2E5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolving Construction Facility</link:label>
    <link:label id="lab_ofc_ConstructionLineOfCreditMember_D4CF6E6EAAE5C4D407CCBF5CEDF3B2E5_label_en-US" xlink:label="lab_ofc_ConstructionLineOfCreditMember_D4CF6E6EAAE5C4D407CCBF5CEDF3B2E5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Construction Line of Credit [Member]</link:label>
    <link:label id="lab_ofc_ConstructionLineOfCreditMember_D4CF6E6EAAE5C4D407CCBF5CEDF3B2E5_documentation_en-US" xlink:label="lab_ofc_ConstructionLineOfCreditMember_D4CF6E6EAAE5C4D407CCBF5CEDF3B2E5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">A contractual arrangement with a lender under which borrowings for construction costs can be made up to a specific amount, and under which borrowings outstanding may be either short-term or long-term, depending upon the particulars.</link:label>
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    <link:label id="lab_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843_terseLabel_en-US" xlink:label="lab_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable rate secured loans</link:label>
    <link:label id="lab_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843_label_en-US" xlink:label="lab_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Rate Secured Debt [Member]</link:label>
    <link:label id="lab_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843_documentation_en-US" xlink:label="lab_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">A collateralized debt obligation (backed by pledge, mortgage or other lien on the entity's assets) bearing fixed interest rates.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_VariableRateSecuredDebtMember" xlink:label="loc_ofc_VariableRateSecuredDebtMember_F55A0DA4014EB8C09E00BF5CEDF38843" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ConstructionLoanPayableMember_CB1F0666600677B27D2ABF5CEDF3FC10_terseLabel_en-US" xlink:label="lab_us-gaap_ConstructionLoanPayableMember_CB1F0666600677B27D2ABF5CEDF3FC10" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other construction loan facilities</link:label>
    <link:label id="lab_us-gaap_ConstructionLoanPayableMember_CB1F0666600677B27D2ABF5CEDF3FC10_label_en-US" xlink:label="lab_us-gaap_ConstructionLoanPayableMember_CB1F0666600677B27D2ABF5CEDF3FC10" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Construction Loan Payable [Member]</link:label>
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    <link:label id="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9_terseLabel_en-US" xlink:label="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revolving Credit Facility</link:label>
    <link:label id="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9_label_en-US" xlink:label="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Credit Facility [Member]</link:label>
    <link:label id="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9_documentation_en-US" xlink:label="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the credit facility which includes the aggregate borrowings of the following facilities: line of credit, letter of credit, and a swingline facility.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_CreditFacilityMember" xlink:label="loc_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9" xlink:to="lab_ofc_CreditFacilityMember_C76D5E6BEDA6CCBC1472BF5CEDF409D9" xlink:type="arc" />
    <link:label id="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40_terseLabel_en-US" xlink:label="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Term Loan Facility</link:label>
    <link:label id="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40_label_en-US" xlink:label="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Term Loan Facility [Member]</link:label>
    <link:label id="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40_documentation_en-US" xlink:label="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the unsecured term loan agreement entered by entity with the group of lenders.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_TermLoanFacilityMember" xlink:label="loc_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40" xlink:to="lab_ofc_TermLoanFacilityMember_46FEF89E47D43790296FBF5CEDF4CE40" xlink:type="arc" />
    <link:label id="lab_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C_terseLabel_en-US" xlink:label="lab_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unsecured notes payable</link:label>
    <link:label id="lab_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C_label_en-US" xlink:label="lab_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unsecured Debt [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnsecuredDebtMember" xlink:label="loc_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C" xlink:to="lab_us-gaap_UnsecuredDebtMember_9054EC7A63D12E7C5F85BF5CEDF40B8C" xlink:type="arc" />
    <link:label id="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38_terseLabel_en-US" xlink:label="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">4.25% Exchangeable Senior Notes</link:label>
    <link:label id="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38_label_en-US" xlink:label="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Exchangeable 4.25 Percent Senior Notes [Member]</link:label>
    <link:label id="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38_documentation_en-US" xlink:label="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the 4.25 percent exchangeable senior notes of the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_Exchangeable425PercentSeniorNotesMember" xlink:label="loc_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38" xlink:to="lab_ofc_Exchangeable425PercentSeniorNotesMember_EF34467F7E8865A52138BF5CEDF43C38" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base [Axis]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base [Axis]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The alternative reference rates that may be used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBaseAxis" xlink:label="loc_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44" xlink:to="lab_ofc_DebtInstrumentVariableRateBaseAxis_319D6A98C7A7496F4439BF5CEDF44A44" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base [Domain]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base [Domain]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Identification of the reference rate that is used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBaseDomain" xlink:label="loc_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793" xlink:to="lab_ofc_DebtInstrumentVariableRateBaseDomain_DC7E1D2C956570C7131EBF5CEDF45793" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LIBOR 30-day</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base LIBOR 30 Day [Member]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The London Interbank Offered Rate (LIBOR), customarily 30-day, used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBaseLibor30DayMember" xlink:label="loc_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633" xlink:to="lab_ofc_DebtInstrumentVariableRateBaseLibor30DayMember_AE7491A471A8B4E70520BF5CEDF4A633" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prime Rate</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base Prime Rate [Member]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The Prime rate used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBasePrimeRateMember" xlink:label="loc_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A" xlink:to="lab_ofc_DebtInstrumentVariableRateBasePrimeRateMember_2E18FC8D72A44D84CC42BF5CEDF4139A" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Federal Funds Rate</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base Federal Funds Rate [Member]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The Federal Funds rate used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember" xlink:label="loc_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3" xlink:to="lab_ofc_DebtInstrumentVariableRateBaseFederalFundsRateMember_DBBD26FB711DA39AE913BF5CEDF41DC3" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LIBOR One-Month Rate</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base LIBOR One Month [Member]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The London Interbank Offered Rate (LIBOR) for a one-month interest period used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember" xlink:label="loc_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A" xlink:to="lab_ofc_DebtInstrumentVariableRateBaseLiborOneMonthMember_6902A9F9EBDD0A3D08CFBF5CEDF4E69A" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LIBOR</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70_label_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument Variable Rate Base LIBOR [Member]</link:label>
    <link:label id="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The London Interbank Offered Rate (LIBOR) used to calculate the variable interest rate of the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentVariableRateBaseLiborMember" xlink:label="loc_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70" xlink:to="lab_ofc_DebtInstrumentVariableRateBaseLiborMember_8F8B05992199076024E3BF5CEDF40B70" xlink:type="arc" />
    <link:label id="lab_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7_terseLabel_en-US" xlink:label="lab_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Range [Axis]</link:label>
    <link:label id="lab_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7_label_en-US" xlink:label="lab_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Range [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeAxis" xlink:label="loc_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7" xlink:to="lab_us-gaap_RangeAxis_6EB87F1D3C00B7D44B79BF5CEDF46ED7" xlink:type="arc" />
    <link:label id="lab_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94_terseLabel_en-US" xlink:label="lab_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Range [Domain]</link:label>
    <link:label id="lab_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94_label_en-US" xlink:label="lab_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Range [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RangeMember" xlink:label="loc_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94" xlink:to="lab_us-gaap_RangeMember_FE549922D496DC34ABE2BF5CEDF4BD94" xlink:type="arc" />
    <link:label id="lab_us-gaap_MaximumMember_51F5193F0387D093845DBF5CEDF5D394_terseLabel_en-US" xlink:label="lab_us-gaap_MaximumMember_51F5193F0387D093845DBF5CEDF5D394" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum</link:label>
    <link:label id="lab_us-gaap_MaximumMember_51F5193F0387D093845DBF5CEDF5D394_label_en-US" xlink:label="lab_us-gaap_MaximumMember_51F5193F0387D093845DBF5CEDF5D394" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Maximum [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MaximumMember" xlink:label="loc_us-gaap_MaximumMember_51F5193F0387D093845DBF5CEDF5D394" xlink:type="locator" />
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    <link:label id="lab_us-gaap_MinimumMember_63A0B45333E16C562BD6BF5CEDF5F73F_terseLabel_en-US" xlink:label="lab_us-gaap_MinimumMember_63A0B45333E16C562BD6BF5CEDF5F73F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Minimum</link:label>
    <link:label id="lab_us-gaap_MinimumMember_63A0B45333E16C562BD6BF5CEDF5F73F_label_en-US" xlink:label="lab_us-gaap_MinimumMember_63A0B45333E16C562BD6BF5CEDF5F73F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minimum [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MinimumMember" xlink:label="loc_us-gaap_MinimumMember_63A0B45333E16C562BD6BF5CEDF5F73F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtInstrumentLineItems_5DD24E90732AE4C52BAEBF5CEDF5835C_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems_5DD24E90732AE4C52BAEBF5CEDF5835C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentLineItems_5DD24E90732AE4C52BAEBF5CEDF5835C_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentLineItems_5DD24E90732AE4C52BAEBF5CEDF5835C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentLineItems" xlink:label="loc_us-gaap_DebtInstrumentLineItems_5DD24E90732AE4C52BAEBF5CEDF5835C" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D498AB281FBCD5C98253BF5CEDF518B2_terseLabel_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D498AB281FBCD5C98253BF5CEDF518B2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum Availability</link:label>
    <link:label id="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D498AB281FBCD5C98253BF5CEDF518B2_label_en-US" xlink:label="lab_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D498AB281FBCD5C98253BF5CEDF518B2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Line of Credit Facility, Maximum Borrowing Capacity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity" xlink:label="loc_us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity_D498AB281FBCD5C98253BF5CEDF518B2" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LongTermDebt_1E9E0943CADFA88007A0BF5CEDF51453_verboseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt_1E9E0943CADFA88007A0BF5CEDF51453" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Carrying Value</link:label>
    <link:label id="lab_us-gaap_LongTermDebt_1E9E0943CADFA88007A0BF5CEDF51453_label_en-US" xlink:label="lab_us-gaap_LongTermDebt_1E9E0943CADFA88007A0BF5CEDF51453" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Debt</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_1E9E0943CADFA88007A0BF5CEDF51453" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stated interest rate (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Stated Percentage</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentage" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3" xlink:to="lab_us-gaap_DebtInstrumentInterestRateStatedPercentage_67B0F212ED6069A2F839BF5CEDF5BEB3" xlink:type="arc" />
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stated Interest Rates, low end of range (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376" xlink:to="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMinimum_D6A14DA6B62A62AF81EABF5CEDF5F376" xlink:type="arc" />
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Stated Interest Rates, high end of range (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum" xlink:label="loc_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227" xlink:to="lab_us-gaap_DebtInstrumentInterestRateStatedPercentageRateRangeMaximum_914FC59D561C637B1E64BF5CEDF5F227" xlink:type="arc" />
    <link:label id="lab_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Description of variable rate basis</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Description of Variable Rate Basis</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentDescriptionOfVariableRateBasis" xlink:label="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D" xlink:to="lab_us-gaap_DebtInstrumentDescriptionOfVariableRateBasis_1126A162FF0F1652EEE1BF5CEDF5694D" xlink:type="arc" />
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable rate, spread (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Basis Spread on Variable Rate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentBasisSpreadOnVariableRate" xlink:label="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A" xlink:to="lab_us-gaap_DebtInstrumentBasisSpreadOnVariableRate_37C48281AAA5839C649EBF5CEDF52A4A" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable rate, spread low end of range (as a percent)</link:label>
    <link:label id="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09_label_en-US" xlink:label="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Basis Spread on Variable Rate, Low End of Range</link:label>
    <link:label id="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The low end of the range of percentage points added to the reference rate to compute the variable rate on the debt instrument.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange" xlink:label="loc_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09" xlink:to="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateLowEndOfRange_469DD86C52A93CBE1F4DBF5CEDF57D09" xlink:type="arc" />
    <link:label id="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateHighEndOfRange_F1A8E0B0488D4D5E90F0BF5CEDF51B0F_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateHighEndOfRange_F1A8E0B0488D4D5E90F0BF5CEDF51B0F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable rate, spread high end of range (as a percent)</link:label>
    <link:label id="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateHighEndOfRange_F1A8E0B0488D4D5E90F0BF5CEDF51B0F_label_en-US" xlink:label="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateHighEndOfRange_F1A8E0B0488D4D5E90F0BF5CEDF51B0F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Basis Spread on Variable Rate, High End of Range</link:label>
    <link:label id="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateHighEndOfRange_F1A8E0B0488D4D5E90F0BF5CEDF51B0F_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentBasisSpreadOnVariableRateHighEndOfRange_F1A8E0B0488D4D5E90F0BF5CEDF51B0F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The high end of the range of percentage points added to the reference rate to compute the variable rate on the debt instrument.</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unamortized premium included in carrying value</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Unamortized Premium</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentUnamortizedPremium" xlink:label="loc_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7" xlink:to="lab_us-gaap_DebtInstrumentUnamortizedPremium_977FFF4263D37A28737DBF5CEDF5A5F7" xlink:type="arc" />
    <link:label id="lab_us-gaap_DebtWeightedAverageInterestRate_2335E2D47B6FE4789FD5BF5CEDF5FBCA_terseLabel_en-US" xlink:label="lab_us-gaap_DebtWeightedAverageInterestRate_2335E2D47B6FE4789FD5BF5CEDF5FBCA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Weighted average interest rate (as a percent)</link:label>
    <link:label id="lab_us-gaap_DebtWeightedAverageInterestRate_2335E2D47B6FE4789FD5BF5CEDF5FBCA_label_en-US" xlink:label="lab_us-gaap_DebtWeightedAverageInterestRate_2335E2D47B6FE4789FD5BF5CEDF5FBCA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt, Weighted Average Interest Rate</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentConvertibleConversionRatio_25F96C35E45A7E05AFD9BF5CEDF6E523_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentConvertibleConversionRatio_25F96C35E45A7E05AFD9BF5CEDF6E523" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exchange rate per $1000 principal amount (in common shares)</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentConvertibleConversionRatio_25F96C35E45A7E05AFD9BF5CEDF6E523_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentConvertibleConversionRatio_25F96C35E45A7E05AFD9BF5CEDF6E523" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Debt Instrument, Convertible, Conversion Ratio</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionRatio" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionRatio_25F96C35E45A7E05AFD9BF5CEDF6E523" xlink:type="locator" />
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    <link:label id="lab_ofc_DebtInstrumentExchangeRatePrincipalAmountUsedInCalculation_A840CE7875F1CB01A105BF5CEDF6E358_terseLabel_en-US" xlink:label="lab_ofc_DebtInstrumentExchangeRatePrincipalAmountUsedInCalculation_A840CE7875F1CB01A105BF5CEDF6E358" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Convertible debt principal amount, basis for exchange</link:label>
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    <link:label id="lab_ofc_DebtInstrumentExchangeRatePrincipalAmountUsedInCalculation_A840CE7875F1CB01A105BF5CEDF6E358_documentation_en-US" xlink:label="lab_ofc_DebtInstrumentExchangeRatePrincipalAmountUsedInCalculation_A840CE7875F1CB01A105BF5CEDF6E358" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The principal amount of notes for purposes of computing the conversion ratio of convertible debt.</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentConvertibleConversionPrice1_375EC7E014FD3256109FBF5CEDF62C9F_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentConvertibleConversionPrice1_375EC7E014FD3256109FBF5CEDF62C9F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exchange price per common share based on exchange rate (in dollars per share)</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentConvertibleConversionPrice1" xlink:label="loc_us-gaap_DebtInstrumentConvertibleConversionPrice1_375EC7E014FD3256109FBF5CEDF62C9F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_F6F2557038503D2BB008BF5CEDF607A9_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount_F6F2557038503D2BB008BF5CEDF607A9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Principal amount of debt</link:label>
    <link:label id="lab_us-gaap_DebtInstrumentCarryingAmount_F6F2557038503D2BB008BF5CEDF607A9_label_en-US" xlink:label="lab_us-gaap_DebtInstrumentCarryingAmount_F6F2557038503D2BB008BF5CEDF607A9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Debt, Gross</link:label>
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    <link:label id="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_7147657FB822AB930863BF5CEDF6944D_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentInterestRateEffectivePercentage_7147657FB822AB930863BF5CEDF6944D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Effective interest rate, including amortization of issuance costs (as a percent)</link:label>
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    <link:label id="lab_us-gaap_InterestExpenseDebtExcludingAmortization_F9EFB616CEDADC1BCC5DBF5CEDF64BBD_terseLabel_en-US" xlink:label="lab_us-gaap_InterestExpenseDebtExcludingAmortization_F9EFB616CEDADC1BCC5DBF5CEDF64BBD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest expense at stated interest rate</link:label>
    <link:label id="lab_us-gaap_InterestExpenseDebtExcludingAmortization_F9EFB616CEDADC1BCC5DBF5CEDF64BBD_label_en-US" xlink:label="lab_us-gaap_InterestExpenseDebtExcludingAmortization_F9EFB616CEDADC1BCC5DBF5CEDF64BBD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Expense, Debt, Excluding Amortization</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestExpenseDebtExcludingAmortization" xlink:label="loc_us-gaap_InterestExpenseDebtExcludingAmortization_F9EFB616CEDADC1BCC5DBF5CEDF64BBD" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AmortizationOfDebtDiscountPremium_D8B4C26DAB4D80422DA9BF5CEDF64C88_verboseLabel_en-US" xlink:label="lab_us-gaap_AmortizationOfDebtDiscountPremium_D8B4C26DAB4D80422DA9BF5CEDF64C88" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Interest expense associated with amortization of discount</link:label>
    <link:label id="lab_us-gaap_AmortizationOfDebtDiscountPremium_D8B4C26DAB4D80422DA9BF5CEDF64C88_label_en-US" xlink:label="lab_us-gaap_AmortizationOfDebtDiscountPremium_D8B4C26DAB4D80422DA9BF5CEDF64C88" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Amortization of Debt Discount (Premium)</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestExpenseDebt" xlink:label="loc_us-gaap_InterestExpenseDebt_603ECB3DB6A84FC7BC11BF5CEDF6B5B1" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_872F1B40636AD669BE2BBF5CEDF6BAD0_terseLabel_en-US" xlink:label="lab_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_872F1B40636AD669BE2BBF5CEDF6BAD0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Initial amount borrowed</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtInstrumentIncreaseAdditionalBorrowings" xlink:label="loc_us-gaap_DebtInstrumentIncreaseAdditionalBorrowings_872F1B40636AD669BE2BBF5CEDF6BAD0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DebtDefaultLongtermDebtAmount_640467F3431F27E1149BBF5CEDF68B2C_terseLabel_en-US" xlink:label="lab_us-gaap_DebtDefaultLongtermDebtAmount_640467F3431F27E1149BBF5CEDF68B2C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Nonrecourse mortgage loan secured by a property in default</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DebtDefaultLongtermDebtAmount" xlink:label="loc_us-gaap_DebtDefaultLongtermDebtAmount_640467F3431F27E1149BBF5CEDF68B2C" xlink:type="locator" />
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    <link:label id="lab_ofc_DebtDefaultEstimatedFairValueOfSecuredProperty_44B39271BC37430CD430BF5CEDF68FC4_documentation_en-US" xlink:label="lab_ofc_DebtDefaultEstimatedFairValueOfSecuredProperty_44B39271BC37430CD430BF5CEDF68FC4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the estimated fair value of property secured by debt for which there has been a default.</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredRentReceivablesNet" xlink:label="loc_us-gaap_DeferredRentReceivablesNet_B9172C0E3D00C09D5FD1C3FF4870F7D8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredRentReceivablesNet_B9172C0E3D00C09D5FD1C3FF4870F7D8" xlink:to="lab_us-gaap_DeferredRentReceivablesNet_B9172C0E3D00C09D5FD1C3FF4870F7D8" xlink:type="arc" />
    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458_terseLabel_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Intangible assets on real estate acquisitions, net</link:label>
    <link:label id="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458_label_en-US" xlink:label="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Intangible Assets, Net (Excluding Goodwill)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IntangibleAssetsNetExcludingGoodwill" xlink:label="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458" xlink:to="lab_us-gaap_IntangibleAssetsNetExcludingGoodwill_2C9CCA1E4427054870DBC3FF48701458" xlink:type="arc" />
    <link:label id="lab_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F_terseLabel_en-US" xlink:label="lab_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred leasing and financing costs, net</link:label>
    <link:label id="lab_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F_label_en-US" xlink:label="lab_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Leasing and Financing Costs Net</link:label>
    <link:label id="lab_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F_documentation_en-US" xlink:label="lab_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Costs incurred by the lessor that are (a) costs to originate a lease incurred in transactions with independent third parties that (i) result directly from and are essential to acquire that lease and (ii) would not have been incurred had that leasing transaction not occurred and (b) certain costs directly related to specified activities performed by the lessor for that lease. Those activities are: evaluating the prospective lessee's financial condition; evaluating and recording guarantees, collateral, and other security arrangements; negotiating lease terms; preparing and processing lease documents; and closing the transaction. This element is net of accumulated amortization, combined with, for an unclassified balance sheet, the carrying amount (net of accumulated amortization) as of the balance sheet date of capitalized costs associated with the issuance of debt instruments (for example, legal, accounting, underwriting, printing, and registration costs) that will be charged against earnings over the life of the debt instruments to which such costs pertain.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DeferredLeasingAndFinancingCostsNet" xlink:label="loc_ofc_DeferredLeasingAndFinancingCostsNet_6477A3F59591F831FE1CC3FF4870D07F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PrepaidExpenseAndOtherAssets_EF1840EFCE5197A3C5A0C3FF48711465_terseLabel_en-US" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssets_EF1840EFCE5197A3C5A0C3FF48711465" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Prepaid expenses and other assets</link:label>
    <link:label id="lab_us-gaap_PrepaidExpenseAndOtherAssets_EF1840EFCE5197A3C5A0C3FF48711465_label_en-US" xlink:label="lab_us-gaap_PrepaidExpenseAndOtherAssets_EF1840EFCE5197A3C5A0C3FF48711465" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid Expense and Other Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssets" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssets_EF1840EFCE5197A3C5A0C3FF48711465" xlink:type="locator" />
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    <link:label id="lab_us-gaap_Assets_4F525A2502284BA94734C3FF48714F65_totalLabel_en-US" xlink:label="lab_us-gaap_Assets_4F525A2502284BA94734C3FF48714F65" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_Assets_4F525A2502284BA94734C3FF48714F65_label_en-US" xlink:label="lab_us-gaap_Assets_4F525A2502284BA94734C3FF48714F65" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_4F525A2502284BA94734C3FF48714F65" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7F44E33F82DD837EE8F2C3FF4871AD0F_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7F44E33F82DD837EE8F2C3FF4871AD0F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities and equity</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7F44E33F82DD837EE8F2C3FF4871AD0F_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7F44E33F82DD837EE8F2C3FF4871AD0F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities and Equity [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesAndStockholdersEquityAbstract" xlink:label="loc_us-gaap_LiabilitiesAndStockholdersEquityAbstract_7F44E33F82DD837EE8F2C3FF4871AD0F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities:</link:label>
    <link:label id="lab_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878_label_en-US" xlink:label="lab_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesAbstract" xlink:label="loc_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878" xlink:to="lab_us-gaap_LiabilitiesAbstract_57A90E981F4563FC1CC5C3FF48719878" xlink:type="arc" />
    <link:label id="lab_us-gaap_LongTermDebt_704439BEC547FD432C83C3FF4871103A_terseLabel_en-US" xlink:label="lab_us-gaap_LongTermDebt_704439BEC547FD432C83C3FF4871103A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Debt, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LongTermDebt" xlink:label="loc_us-gaap_LongTermDebt_704439BEC547FD432C83C3FF4871103A" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts payable and accrued expenses</link:label>
    <link:label id="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933_label_en-US" xlink:label="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts Payable and Accrued Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent" xlink:label="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933" xlink:to="lab_us-gaap_AccountsPayableAndAccruedLiabilitiesCurrentAndNoncurrent_CAA76A94BE57AD3E17BCC3FF48714933" xlink:type="arc" />
    <link:label id="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6_terseLabel_en-US" xlink:label="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rents received in advance and security deposits</link:label>
    <link:label id="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6_label_en-US" xlink:label="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Advance Rent and Security Deposit Liability</link:label>
    <link:label id="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6_documentation_en-US" xlink:label="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount at the balance sheet date that has been received by the entity that represents collections of cash or other assets related to real estate operations revenue for which revenue has not yet been recognized and money paid in advance to protect the provider of a product or service, such as a lessor, against damage or nonpayment by the buyer or tenant (lessee) during the term of the agreement. Such damages may include physical damage to the property, theft of property, and other contractual breaches. Security deposits held may be interest or noninterest bearing.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AdvanceRentAndSecurityDepositLiability" xlink:label="loc_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6" xlink:to="lab_ofc_AdvanceRentAndSecurityDepositLiability_BDFD72F5D561C3A9E978C3FF487198E6" xlink:type="arc" />
    <link:label id="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080_terseLabel_en-US" xlink:label="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dividends and distributions payable</link:label>
    <link:label id="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080_label_en-US" xlink:label="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends and Distributions Payable</link:label>
    <link:label id="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080_documentation_en-US" xlink:label="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carrying value as of the balance sheet date of dividends declared but unpaid on equity securities issued by the entity and outstanding and distributions payable on noncontrolling equity interests in the Operating Partnership.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DividendsAndDistributionsPayable" xlink:label="loc_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080" xlink:to="lab_ofc_DividendsAndDistributionsPayable_7F1DD9B0976CB5B3597EC3FF4871D080" xlink:type="arc" />
    <link:label id="lab_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E_terseLabel_en-US" xlink:label="lab_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred revenue associated with operating leases</link:label>
    <link:label id="lab_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E_label_en-US" xlink:label="lab_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Revenue Operating Leases</link:label>
    <link:label id="lab_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E_documentation_en-US" xlink:label="lab_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element includes liabilities associated with the acquisition of an off-market lease when the terms of the lease are unfavorable to the market terms for the lease at the date of acquisition. Also includes the cumulative liability resulting from the difference between the rental payments required by a lease agreement and the rental income or expense recognized on a straight-line basis, or other systematic and rational basis more representative of the time pattern in which use or benefit is granted or derived from the leased property, expected to be recognized in income or expense over the term of the leased property, by the lessor or lessee, respectively.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DeferredRevenueOperatingLeases" xlink:label="loc_ofc_DeferredRevenueOperatingLeases_B9C62DE9ECCDB5B7F137C3FF4871FC9E" xlink:type="locator" />
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    <link:label id="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_9A7347CCC26408E25C91C3FF487278F2_terseLabel_en-US" xlink:label="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_9A7347CCC26408E25C91C3FF487278F2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Distributions received in excess of investment in unconsolidated real estate joint venture</link:label>
    <link:label id="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_9A7347CCC26408E25C91C3FF487278F2_label_en-US" xlink:label="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_9A7347CCC26408E25C91C3FF487278F2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Distributions Received in Excess of Investment in Unconsolidated Real Estate Joint Venture</link:label>
    <link:label id="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_9A7347CCC26408E25C91C3FF487278F2_documentation_en-US" xlink:label="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_9A7347CCC26408E25C91C3FF487278F2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Carrying value as of balance sheet date of investments in the following types of entities when distributions received on such investments exceed amounts invested: (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from or payable to such an entity and adjustments for other than temporary impairment losses recognized.</link:label>
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    <link:label id="lab_us-gaap_Liabilities_BB2C97489467BA7A6B93C3FF487275C5_label_en-US" xlink:label="lab_us-gaap_Liabilities_BB2C97489467BA7A6B93C3FF487275C5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities</link:label>
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    <link:label id="lab_us-gaap_StockholdersEquityAbstract_B57AEA1C24D2A5D55FFBC3FF4872CDBD_label_en-US" xlink:label="lab_us-gaap_StockholdersEquityAbstract_B57AEA1C24D2A5D55FFBC3FF4872CDBD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stockholders' Equity Attributable to Parent [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityAbstract" xlink:label="loc_us-gaap_StockholdersEquityAbstract_B57AEA1C24D2A5D55FFBC3FF4872CDBD" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PreferredStockValue_B2BB992BBD79AE2054CAC3FF4872EA70_label_en-US" xlink:label="lab_us-gaap_PreferredStockValue_B2BB992BBD79AE2054CAC3FF4872EA70" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Preferred Stock, Value, Issued</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_B2BB992BBD79AE2054CAC3FF4872EA70" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CommonStockValue_92A195E467AF3D2E3083C3FF4872165C_label_en-US" xlink:label="lab_us-gaap_CommonStockValue_92A195E467AF3D2E3083C3FF4872165C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Stock, Value, Issued</link:label>
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    <link:label id="lab_us-gaap_AdditionalPaidInCapital_1A8304AE001AD4B88E37C3FF4872E272_label_en-US" xlink:label="lab_us-gaap_AdditionalPaidInCapital_1A8304AE001AD4B88E37C3FF4872E272" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Additional Paid in Capital</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdditionalPaidInCapital" xlink:label="loc_us-gaap_AdditionalPaidInCapital_1A8304AE001AD4B88E37C3FF4872E272" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccumulatedDistributionsInExcessOfNetIncome" xlink:label="loc_us-gaap_AccumulatedDistributionsInExcessOfNetIncome_5150F62D6BE880B0AFFEC3FF487359DC" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StockholdersEquity_6F678AEC5B190D762684C3FF48739D2D_label_en-US" xlink:label="lab_us-gaap_StockholdersEquity_6F678AEC5B190D762684C3FF48739D2D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stockholders' Equity Attributable to Parent</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PrepaidExpenseAndOtherAssetsAbstract" xlink:label="loc_us-gaap_PrepaidExpenseAndOtherAssetsAbstract_4675F9F6B78DD4D52E1835090860634F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PrepaidExpenseAndOtherAssetsAbstract_4675F9F6B78DD4D52E1835090860634F" xlink:to="lab_us-gaap_PrepaidExpenseAndOtherAssetsAbstract_4675F9F6B78DD4D52E1835090860634F" xlink:type="arc" />
    <link:label id="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA_terseLabel_en-US" xlink:label="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Mortgage and Other Investing Receivables [Table]</link:label>
    <link:label id="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA_label_en-US" xlink:label="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Mortgage and Other Investing Receivables [Table]</link:label>
    <link:label id="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA_documentation_en-US" xlink:label="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tabular disclosure of the carrying amounts of mortgage and other investing receivables, by major class.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable" xlink:label="loc_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA" xlink:to="lab_ofc_ScheduleOfMortgageAndOtherInvestingReceivablesTable_E4E837071620EC3F21873509086007AA" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938_terseLabel_en-US" xlink:label="lab_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts, Notes, Loans and Financing Receivable by Receivable Type [Axis]</link:label>
    <link:label id="lab_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938_label_en-US" xlink:label="lab_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounts, Notes, Loans and Financing Receivable by Receivable Type [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis" xlink:label="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938" xlink:to="lab_us-gaap_AccountsNotesLoansAndFinancingReceivableByReceivableTypeAxis_B72338C8BE02C591AFE335090860C938" xlink:type="arc" />
    <link:label id="lab_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2_terseLabel_en-US" xlink:label="lab_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Receivable Type [Domain]</link:label>
    <link:label id="lab_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2_label_en-US" xlink:label="lab_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Receivable Type [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ReceivableTypeDomain" xlink:label="loc_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2" xlink:to="lab_us-gaap_ReceivableTypeDomain_025177A611B3F1F479E835090860D6A2" xlink:type="arc" />
    <link:label id="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F_terseLabel_en-US" xlink:label="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Notes receivable from City of Huntsville</link:label>
    <link:label id="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F_label_en-US" xlink:label="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Notes Receivable from City of Huntsville [Member]</link:label>
    <link:label id="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F_documentation_en-US" xlink:label="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents notes receivable from City of Huntsville.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NotesReceivableFromCityOfHuntsvilleMember" xlink:label="loc_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F" xlink:to="lab_ofc_NotesReceivableFromCityOfHuntsvilleMember_0BAFFFAC6419DE0D082D35090861AB3F" xlink:type="arc" />
    <link:label id="lab_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66_terseLabel_en-US" xlink:label="lab_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage loans receivable</link:label>
    <link:label id="lab_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66_label_en-US" xlink:label="lab_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgage Receivable [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MortgageReceivablesMember" xlink:label="loc_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66" xlink:to="lab_us-gaap_MortgageReceivablesMember_158552CB379F5B24C50E350908615C66" xlink:type="arc" />
    <link:label id="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447_terseLabel_en-US" xlink:label="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating notes receivable</link:label>
    <link:label id="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447_label_en-US" xlink:label="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Operating Notes Receivable [Member]</link:label>
    <link:label id="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447_documentation_en-US" xlink:label="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents operating notes receivable due from tenants with maturities beyond one year.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_LongTermOperatingNotesReceivableMember" xlink:label="loc_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447" xlink:to="lab_ofc_LongTermOperatingNotesReceivableMember_38E2B5AC88F7E04C5F0D350908612447" xlink:type="arc" />
    <link:label id="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830_terseLabel_en-US" xlink:label="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage and other investing receivables</link:label>
    <link:label id="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830_label_en-US" xlink:label="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgage and Other Investing Receivables [Line Items]</link:label>
    <link:label id="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830_documentation_en-US" xlink:label="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MortgageAndOtherInvestingReceivablesLineItems" xlink:label="loc_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830" xlink:to="lab_ofc_MortgageAndOtherInvestingReceivablesLineItems_A6F5795E5A277AD1F5B3350908619830" xlink:type="arc" />
    <link:label id="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8_terseLabel_en-US" xlink:label="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Mortgage and other investing receivables</link:label>
    <link:label id="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8_label_en-US" xlink:label="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgage and Other Investing Receivables</link:label>
    <link:label id="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8_documentation_en-US" xlink:label="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">An amount classified as an investment activity representing an agreement for an unconditional promise by the maker to pay the Entity (holder) a definite sum of money at a future date, net of any write-downs taken for collection uncertainty on the part of the holder. Such amount may include accrued interest receivable in accordance with the terms of the note. The note also may contain provisions and related items including a discount or premium, payable on demand, secured, or unsecured, interest bearing or noninterest bearing, among a myriad of other features and characteristics. This amount does not include amounts related to receivables held-for-sale.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MortgageAndOtherInvestingReceivables" xlink:label="loc_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8" xlink:to="lab_ofc_MortgageAndOtherInvestingReceivables_26D65ABF825FD769D3CB35090861F0C8" xlink:type="arc" />
    <link:label id="lab_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA_terseLabel_en-US" xlink:label="lab_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of mortgage loans receivable</link:label>
    <link:label id="lab_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA_label_en-US" xlink:label="lab_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Mortgage Loans Receivable, Number</link:label>
    <link:label id="lab_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA_documentation_en-US" xlink:label="lab_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of loans secured by properties included in mortgage loans receivable.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MortgageLoansReceivableNumber" xlink:label="loc_ofc_MortgageLoansReceivableNumber_0361A9399896E01DF2313509086190AA" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1_terseLabel_en-US" xlink:label="lab_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value of mortgage and other investing receivables</link:label>
    <link:label id="lab_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1_label_en-US" xlink:label="lab_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Loans Receivable, Fair Value Disclosure</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LoansReceivableFairValueDisclosure" xlink:label="loc_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1" xlink:to="lab_us-gaap_LoansReceivableFairValueDisclosure_CB72D36D04287436E19E3509086124B1" xlink:type="arc" />
    <link:label id="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7_terseLabel_en-US" xlink:label="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Notes Receivable</link:label>
    <link:label id="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7_label_en-US" xlink:label="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Notes Receivable [Abstract]</link:label>
    <link:label id="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7_documentation_en-US" xlink:label="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OperatingNotesReceivableAbstract" xlink:label="loc_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7" xlink:to="lab_ofc_OperatingNotesReceivableAbstract_019175FF1607145F706935090861F8F7" xlink:type="arc" />
    <link:label id="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C_terseLabel_en-US" xlink:label="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating notes receivables due from tenants with terms exceeding one year</link:label>
    <link:label id="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C_label_en-US" xlink:label="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Notes Receivable Long-term</link:label>
    <link:label id="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C_documentation_en-US" xlink:label="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of operating notes receivables due from tenants with terms exceeding one year.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OperatingNotesReceivableLongTerm" xlink:label="loc_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C" xlink:to="lab_ofc_OperatingNotesReceivableLongTerm_C03DA5E12E0134516FD035090861FB4C" xlink:type="arc" />
    <link:label id="lab_us-gaap_StatementOfCashFlowsAbstract_E9EF9F8B2E2680A6FB26C422D98B4196_label_en-US" xlink:label="lab_us-gaap_StatementOfCashFlowsAbstract_E9EF9F8B2E2680A6FB26C422D98B4196" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement of Cash Flows [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementOfCashFlowsAbstract" xlink:label="loc_us-gaap_StatementOfCashFlowsAbstract_E9EF9F8B2E2680A6FB26C422D98B4196" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementOfCashFlowsAbstract_E9EF9F8B2E2680A6FB26C422D98B4196" xlink:to="lab_us-gaap_StatementOfCashFlowsAbstract_E9EF9F8B2E2680A6FB26C422D98B4196" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash flows from operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivitiesAbstract_65ADEA1576CD87EBF16AC422D98C96D9" xlink:type="arc" />
    <link:label id="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662_terseLabel_en-US" xlink:label="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues from real estate operations received</link:label>
    <link:label id="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662_label_en-US" xlink:label="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues from Real Estate Operations Received</link:label>
    <link:label id="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662_documentation_en-US" xlink:label="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash received for rents, tenant recoveries and other real estate operations during the current period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RevenuesFromRealEstateOperationsReceived" xlink:label="loc_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662" xlink:to="lab_ofc_RevenuesFromRealEstateOperationsReceived_92CCBA410FC5931A4542C422D98C0662" xlink:type="arc" />
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C_terseLabel_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Construction contract and other service revenues received</link:label>
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C_label_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Construction Contract and Other Service Revenues Received</link:label>
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C_documentation_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash received for building and real estate development, which may include improvements (such as drainage, utilities, grading and subdividing) to a parcel of land, and general contracting services and from the sale of other goods or rendering of other services.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ConstructionContractAndOtherServiceRevenuesReceived" xlink:label="loc_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C" xlink:to="lab_ofc_ConstructionContractAndOtherServiceRevenuesReceived_5A88352E05656B1D952AC422D98C8D4C" xlink:type="arc" />
    <link:label id="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9_negatedLabel_en-US" xlink:label="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Property operating expenses paid</link:label>
    <link:label id="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9_label_en-US" xlink:label="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property Operating Expenses Paid</link:label>
    <link:label id="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9_documentation_en-US" xlink:label="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the amount of cash paid during the current period for costs that are directly related to generation of revenues from leased and rented properties or equipment.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PropertyOperatingExpensesPaid" xlink:label="loc_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9" xlink:to="lab_ofc_PropertyOperatingExpensesPaid_1C487C52578DE6A123A7C422D98C13C9" xlink:type="arc" />
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C_negatedLabel_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Construction contract and other service expenses paid</link:label>
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C_label_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Construction Contract and Other Service Expenses Paid</link:label>
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C_documentation_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash payments for costs related to construction and development services and other service operations during the current period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ConstructionContractAndOtherServiceExpensesPaid" xlink:label="loc_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C" xlink:to="lab_ofc_ConstructionContractAndOtherServiceExpensesPaid_0C88043E9373227C821FC422D98C501C" xlink:type="arc" />
    <link:label id="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182_negatedLabel_en-US" xlink:label="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">General and administrative and business development expenses paid</link:label>
    <link:label id="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182_label_en-US" xlink:label="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">General and Administrative and Business Development Expenses Paid</link:label>
    <link:label id="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182_documentation_en-US" xlink:label="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Cash payments for costs of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line, and cash pay</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid" xlink:label="loc_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182" xlink:to="lab_ofc_GeneralAndAdministrativeAndBusinessDevelopmentExpensesPaid_283FE6C5472A73466BF8C422D98CA182" xlink:type="arc" />
    <link:label id="lab_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A_negatedLabel_en-US" xlink:label="lab_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Interest expense paid</link:label>
    <link:label id="lab_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A_label_en-US" xlink:label="lab_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Paid, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_InterestPaidNet" xlink:label="loc_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A" xlink:to="lab_us-gaap_InterestPaidNet_CB2CEA2D7841E87780C4C422D98CB37A" xlink:type="arc" />
    <link:label id="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F_negatedLabel_en-US" xlink:label="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Cash settlement of interest rate derivatives</link:label>
    <link:label id="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F_label_en-US" xlink:label="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Derivative Instrument Operating Activities</link:label>
    <link:label id="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F_documentation_en-US" xlink:label="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash outflow for derivative instruments during the period, which are classified as operating activities, excluding those designated as hedging instruments.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PaymentsForDerivativeInstrumentOperatingActivities" xlink:label="loc_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F" xlink:to="lab_ofc_PaymentsForDerivativeInstrumentOperatingActivities_CDFBD805DB93F225B19DC422D98CFB8F" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of trading marketable securities</link:label>
    <link:label id="lab_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188_label_en-US" xlink:label="lab_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from (Payments for) Trading Securities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromPaymentsForTradingSecurities" xlink:label="loc_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188" xlink:to="lab_us-gaap_ProceedsFromPaymentsForTradingSecurities_9EEF148F4C0DB55D65EEC422D98DA188" xlink:type="arc" />
    <link:label id="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8_terseLabel_en-US" xlink:label="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest and other income received</link:label>
    <link:label id="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8_label_en-US" xlink:label="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest and Other Income Received</link:label>
    <link:label id="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8_documentation_en-US" xlink:label="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of cash received during the current period for aggregate amount of other income amounts resulting from ancillary business-related activities (that is, excluding major activities considered part of the normal operations of the business</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestAndOtherIncomeReceived" xlink:label="loc_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8" xlink:to="lab_ofc_InterestAndOtherIncomeReceived_C8BD4F4D6CA84A944C79C422D98DA7C8" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Payments in connection with early extinguishment of debt</link:label>
    <link:label id="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627_label_en-US" xlink:label="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments of Debt Extinguishment Costs</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsOfDebtExtinguishmentCosts" xlink:label="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627" xlink:to="lab_us-gaap_PaymentsOfDebtExtinguishmentCosts_AA60C3FF17BAA180D749C422D98D2627" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86_negatedLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Income taxes paid</link:label>
    <link:label id="lab_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86_label_en-US" xlink:label="lab_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Taxes Paid</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxesPaid" xlink:label="loc_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86" xlink:to="lab_us-gaap_IncomeTaxesPaid_C830369B3B8E14A3E852C422D98D1C86" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by operating activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Operating Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInOperatingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41" xlink:to="lab_us-gaap_NetCashProvidedByUsedInOperatingActivities_984F2B97482B8BD0AA52C422D98DDB41" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash flows from investing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivitiesAbstract_CA5316D0A8B3363C4BD6C422D98DE287" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F_terseLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Purchases of and additions to properties</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire and Develop Real Estate [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract" xlink:label="loc_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F" xlink:to="lab_us-gaap_PaymentsToAcquireAndDevelopRealEstateAbstract_A609B8482C2F73A14E45C422D98D723F" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToDevelopRealEstateAssets_7C727BFC6E5C5669A4C2C422D98D4A99_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToDevelopRealEstateAssets_7C727BFC6E5C5669A4C2C422D98D4A99" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Construction, development and redevelopment</link:label>
    <link:label id="lab_us-gaap_PaymentsToDevelopRealEstateAssets_7C727BFC6E5C5669A4C2C422D98D4A99_label_en-US" xlink:label="lab_us-gaap_PaymentsToDevelopRealEstateAssets_7C727BFC6E5C5669A4C2C422D98D4A99" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Develop Real Estate Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToDevelopRealEstateAssets" xlink:label="loc_us-gaap_PaymentsToDevelopRealEstateAssets_7C727BFC6E5C5669A4C2C422D98D4A99" xlink:type="locator" />
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    <link:label id="lab_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2_negatedLabel_en-US" xlink:label="lab_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Tenant improvements on operating properties</link:label>
    <link:label id="lab_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2_label_en-US" xlink:label="lab_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tenant Improvements on Operating Properties</link:label>
    <link:label id="lab_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2_documentation_en-US" xlink:label="lab_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Payments for improvements having a life longer than one year that were made for the benefit of one or more tenants.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_TenantImprovementsOnOperatingProperties" xlink:label="loc_ofc_TenantImprovementsOnOperatingProperties_1A46AAE491E918CEE57FC422D98DA2B2" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other capital improvements on operating properties</link:label>
    <link:label id="lab_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA_label_en-US" xlink:label="lab_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Capital Improvements</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsForCapitalImprovements" xlink:label="loc_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA" xlink:to="lab_us-gaap_PaymentsForCapitalImprovements_DB2D106AB9B21FEC2420C422D98DEECA" xlink:type="arc" />
    <link:label id="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_8470998EB290FF1ACA4FC422D98D547D_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_8470998EB290FF1ACA4FC422D98D547D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sales of properties</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment" xlink:label="loc_us-gaap_ProceedsFromSaleOfRealEstateHeldforinvestment_8470998EB290FF1ACA4FC422D98D547D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from sale of equity method investment</link:label>
    <link:label id="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B_label_en-US" xlink:label="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Proceeds from Sale of Equity Method Investments</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromSaleOfEquityMethodInvestments" xlink:label="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B" xlink:to="lab_us-gaap_ProceedsFromSaleOfEquityMethodInvestments_9393164CB9F09A493B42C422D98D543B" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsToAcquireNotesReceivable_A4125BD7ED4112164A2FC422D98EC6C5_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireNotesReceivable_A4125BD7ED4112164A2FC422D98EC6C5" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Mortgage and other loan receivables funded or acquired</link:label>
    <link:label id="lab_us-gaap_PaymentsToAcquireNotesReceivable_A4125BD7ED4112164A2FC422D98EC6C5_label_en-US" xlink:label="lab_us-gaap_PaymentsToAcquireNotesReceivable_A4125BD7ED4112164A2FC422D98EC6C5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments to Acquire Notes Receivable</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsToAcquireNotesReceivable" xlink:label="loc_us-gaap_PaymentsToAcquireNotesReceivable_A4125BD7ED4112164A2FC422D98EC6C5" xlink:type="locator" />
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    <link:label id="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2_negatedLabel_en-US" xlink:label="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Leasing costs paid</link:label>
    <link:label id="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2_label_en-US" xlink:label="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for Leasing Costs</link:label>
    <link:label id="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2_documentation_en-US" xlink:label="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The cash outflow related to deferred leasing costs paid by the entity to lease rentable space.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PaymentsForLeasingCosts" xlink:label="loc_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2" xlink:to="lab_ofc_PaymentsForLeasingCosts_BFF71E6E0D605287FA66C422D98E27B2" xlink:type="arc" />
    <link:label id="lab_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_655400A8F97989F427DCC422D98EECF0_negatedLabel_en-US" xlink:label="lab_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_655400A8F97989F427DCC422D98EECF0" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_655400A8F97989F427DCC422D98EECF0_label_en-US" xlink:label="lab_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_655400A8F97989F427DCC422D98EECF0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Payments for (Proceeds from) Other Investing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PaymentsForProceedsFromOtherInvestingActivities" xlink:label="loc_us-gaap_PaymentsForProceedsFromOtherInvestingActivities_655400A8F97989F427DCC422D98EECF0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6_totalLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net cash provided by (used in) investing activities</link:label>
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6_label_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Cash Provided by (Used in) Investing Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInInvestingActivities" xlink:label="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6" xlink:to="lab_us-gaap_NetCashProvidedByUsedInInvestingActivities_963A2141FADA2F2F33A2C422D98E3EC6" xlink:type="arc" />
    <link:label id="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5A3257E5F1DF237DDC0DC422D98E39EF_terseLabel_en-US" xlink:label="lab_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5A3257E5F1DF237DDC0DC422D98E39EF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cash flows from financing activities</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract" xlink:label="loc_us-gaap_NetCashProvidedByUsedInFinancingActivitiesAbstract_5A3257E5F1DF237DDC0DC422D98E39EF" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebtAbstract_752C210552CA9403347DC422D98E64D1_terseLabel_en-US" xlink:label="lab_us-gaap_ProceedsFromIssuanceOfLongTermDebtAbstract_752C210552CA9403347DC422D98E64D1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Proceeds from debt</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ProceedsFromIssuanceOfLongTermDebtAbstract" xlink:label="loc_us-gaap_ProceedsFromIssuanceOfLongTermDebtAbstract_752C210552CA9403347DC422D98E64D1" xlink:type="locator" />
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    <link:label id="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_19D869D00A7DF86B26D6C422D9908892_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_19D869D00A7DF86B26D6C422D9908892" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Realized Gain (Loss) on Disposal</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal" xlink:label="loc_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_19D869D00A7DF86B26D6C422D9908892" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_19D869D00A7DF86B26D6C422D9908892" xlink:to="lab_us-gaap_EquityMethodInvestmentRealizedGainLossOnDisposal_19D869D00A7DF86B26D6C422D9908892" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensation_81C99322CD3554ACFBC3C422D990F1E1_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_81C99322CD3554ACFBC3C422D990F1E1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based compensation</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensation_81C99322CD3554ACFBC3C422D990F1E1_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensation_81C99322CD3554ACFBC3C422D990F1E1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensation" xlink:label="loc_us-gaap_ShareBasedCompensation_81C99322CD3554ACFBC3C422D990F1E1" xlink:type="locator" />
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    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C_negatedLabel_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C_label_en-US" xlink:label="lab_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Noncash Income (Expense)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherNoncashIncomeExpense" xlink:label="loc_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C" xlink:to="lab_us-gaap_OtherNoncashIncomeExpense_AA40F6FB81CC71C42F01C422D990FD7C" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8_terseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Changes in operating assets and liabilities:</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Operating Capital [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInOperatingCapitalAbstract" xlink:label="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8" xlink:to="lab_us-gaap_IncreaseDecreaseInOperatingCapitalAbstract_109385B78C75336BC2DAC422D990C4E8" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB_negatedLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Decrease in accounts receivable</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accounts Receivable</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInAccountsReceivable" xlink:label="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB" xlink:to="lab_us-gaap_IncreaseDecreaseInAccountsReceivable_6A2EE3B4A1D5D71BEAD8C422D9901FDB" xlink:type="arc" />
    <link:label id="lab_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20_negatedLabel_en-US" xlink:label="lab_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Decrease in restricted cash and marketable securities</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20_label_en-US" xlink:label="lab_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Marketable Securities and Restricted Cash</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20_documentation_en-US" xlink:label="lab_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The net cash inflow (outflow) for the net change associated with funds that are not available for withdrawal or use (such as funds held in escrow) and are associated with underlying transactions that are classified as operating activities and marketable securities.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash" xlink:label="loc_ofc_IncreaseDecreaseInMarketableSecuritiesAndRestrictedCash_68417722556A8B2AF44BC422D990BC20" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Decrease in prepaid expenses and other assets</link:label>
    <link:label id="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9_label_en-US" xlink:label="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Prepaid Expense and Other Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets" xlink:label="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9" xlink:to="lab_us-gaap_IncreaseDecreaseInPrepaidDeferredExpenseAndOtherAssets_E0B4E658CA8F4DE30DEAC422D990E1F9" xlink:type="arc" />
    <link:label id="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B_terseLabel_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in accounts payable, accrued expenses and other liabilities</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B_label_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accounts Payable and Other Accrued Liabilities</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B_documentation_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The net change during the reporting period in the aggregate amount of obligations and expenses incurred but not paid and other liabilities.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities" xlink:label="loc_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B" xlink:to="lab_ofc_IncreaseDecreaseInAccountsPayableAndOtherAccruedLiabilities_FAF495B470E9FBEA1570C422D990638B" xlink:type="arc" />
    <link:label id="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1_terseLabel_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in rents received in advance and security deposits</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1_label_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Advance Rent and Security Deposit Liability</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1_documentation_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The net change in amount that has been received by the entity that represents collections of cash or other assets related to real estate operations revenue for which revenue has not yet been recognized and security deposits.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability" xlink:label="loc_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1" xlink:to="lab_ofc_IncreaseDecreaseInAdvanceRentAndSecurityDepositLiability_7A42164F7D000A784C9CC422D990E7E1" xlink:type="arc" />
    <link:label id="lab_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346_terseLabel_en-US" xlink:label="lab_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in interest rate derivatives in connection with cash settlement</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346_label_en-US" xlink:label="lab_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase Decrease In Interest Rate Derivatives in Connection With Cash Settlement</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346_documentation_en-US" xlink:label="lab_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The decrease in derivatives relating to the cash outflow for derivative instruments during the period, which are classified as operating activities, excluding those designated as hedging instruments.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement" xlink:label="loc_ofc_IncreaseDecreaseInInterestRateDerivativesInConnectionWithCashSettlement_77067F6720C372DBB86EC422D9909346" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_B18BC1FB2C3A32E81BB5C422D9904134_terseLabel_en-US" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_B18BC1FB2C3A32E81BB5C422D9904134" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Supplemental schedule of non-cash investing and financing activities:</link:label>
    <link:label id="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_B18BC1FB2C3A32E81BB5C422D9904134_label_en-US" xlink:label="lab_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_B18BC1FB2C3A32E81BB5C422D9904134" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract" xlink:label="loc_us-gaap_CashFlowNoncashInvestingAndFinancingActivitiesDisclosureAbstract_B18BC1FB2C3A32E81BB5C422D9904134" xlink:type="locator" />
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    <link:label id="lab_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7_terseLabel_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">(Decrease) increase in accrued capital improvements, leasing and other investing activity costs</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7_label_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Accrued Capital Improvements Leasing and Other Investing Activity Costs</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7_documentation_en-US" xlink:label="lab_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The net change during the reporting period in future cash outflow to pay for purchases of fixed assets, construction in progress expenditures, deferred leasing costs and other investing activity costs that have occurred.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts" xlink:label="loc_ofc_IncreaseDecreaseInAccruedCapitalImprovementsLeasingAndOtherInvestingActivityCosts_42FEBBFD33887B50D709C422D9904CE7" xlink:type="locator" />
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    <link:label id="lab_us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1_C5E7A3C803A927AA58A9C422D99010F2_terseLabel_en-US" xlink:label="lab_us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1_C5E7A3C803A927AA58A9C422D99010F2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Increase in property, debt and other liabilities in connection with acquisitions</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1" xlink:label="loc_us-gaap_NoncashOrPartNoncashAcquisitionNetNonmonetaryAssetsAcquiredLiabilitiesAssumed1_C5E7A3C803A927AA58A9C422D99010F2" xlink:type="locator" />
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    <link:label id="lab_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181_terseLabel_en-US" xlink:label="lab_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in fair value of derivatives applied to AOCL and noncontrolling interests</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181_label_en-US" xlink:label="lab_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Increase (Decrease) in Fair Value of Derivatives Applied to AOCL and Noncontrolling Interests</link:label>
    <link:label id="lab_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181_documentation_en-US" xlink:label="lab_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Increase in fair value of derivatives applied to Accumulated Other Comprehensive (Loss) Profit and noncontrolling interests</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests" xlink:label="loc_ofc_IncreaseDecreaseInFairValueOfDerivativesAppliedToAoclAndNoncontrollingInterests_18E6751DC9880194D7EDC422D9911181" xlink:type="locator" />
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    <link:label id="lab_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275_verboseLabel_en-US" xlink:label="lab_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Dividends/distributions payable</link:label>
    <link:label id="lab_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275_label_en-US" xlink:label="lab_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends Distributions Payable</link:label>
    <link:label id="lab_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275_documentation_en-US" xlink:label="lab_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The aggregate amount of dividends declared but unpaid on equity securities issued by the entity and outstanding and distributions payable on noncontrolling equity interests in the Operating Partnership.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DividendsDistributionsPayable" xlink:label="loc_ofc_DividendsDistributionsPayable_0AA8B92907F18BDE8075C422D991B275" xlink:type="locator" />
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    <link:label id="lab_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E_terseLabel_en-US" xlink:label="lab_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Decrease in noncontrolling interests and increase in shareholders' equity in connection with the conversion of common units into common shares</link:label>
    <link:label id="lab_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E_label_en-US" xlink:label="lab_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Change Stock Issued During Period Value Conversion of Units</link:label>
    <link:label id="lab_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E_documentation_en-US" xlink:label="lab_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Change in equity from stock issued during the period upon the conversion of units. An example of a convertible unit is an umbrella partnership real investment trust unit (UPREIT unit).</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits" xlink:label="loc_ofc_EquityChangeStockIssuedDuringPeriodValueConversionOfUnits_689244065D85B051F062C422D991F51E" xlink:type="locator" />
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    <link:label id="lab_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E_terseLabel_en-US" xlink:label="lab_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustments to noncontrolling interests resulting from changes in ownership of Operating Partnership by COPT</link:label>
    <link:label id="lab_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E_label_en-US" xlink:label="lab_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Change Adjustments to Additional Paid in Capital Reallocation of Minority Interest</link:label>
    <link:label id="lab_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E_documentation_en-US" xlink:label="lab_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Adjustments to additional paid in capital as a result of a reallocation of a subsidiary's stockholders' equity to noncontrolling interest due to the subsidiary issuing stock. This reallocation is from a capital transaction.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest" xlink:label="loc_ofc_EquityChangeAdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_10A1A5E136FF13CF5355C422D991DA4E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTable_E466D4EA8CCA08DABABA39B9FF92315E_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTable_E466D4EA8CCA08DABABA39B9FF92315E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping [Table]</link:label>
    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingTable_E466D4EA8CCA08DABABA39B9FF92315E_label_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingTable_E466D4EA8CCA08DABABA39B9FF92315E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingTable" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingTable_E466D4EA8CCA08DABABA39B9FF92315E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_E7E30F3E3CB9BAB6B6C239B9FF922FEE_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_E7E30F3E3CB9BAB6B6C239B9FF922FEE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis]</link:label>
    <link:label id="lab_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_E7E30F3E3CB9BAB6B6C239B9FF922FEE_label_en-US" xlink:label="lab_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_E7E30F3E3CB9BAB6B6C239B9FF922FEE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, by Balance Sheet Grouping, Disclosure Item Amounts [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis" xlink:label="loc_us-gaap_FairValueByBalanceSheetGroupingDisclosureItemAmountsAxis_E7E30F3E3CB9BAB6B6C239B9FF922FEE" xlink:type="locator" />
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    <link:label id="lab_us-gaap_FairValueDisclosureItemAmountsDomain_8E976250D539B49A91DF39B9FF92E80A_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueDisclosureItemAmountsDomain_8E976250D539B49A91DF39B9FF92E80A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair Value, Disclosure Item Amounts [Domain]</link:label>
    <link:label id="lab_us-gaap_FairValueDisclosureItemAmountsDomain_8E976250D539B49A91DF39B9FF92E80A_label_en-US" xlink:label="lab_us-gaap_FairValueDisclosureItemAmountsDomain_8E976250D539B49A91DF39B9FF92E80A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Disclosure Item Amounts [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueDisclosureItemAmountsDomain" xlink:label="loc_us-gaap_FairValueDisclosureItemAmountsDomain_8E976250D539B49A91DF39B9FF92E80A" xlink:type="locator" />
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    <link:label id="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_EACFA9F922926FF73F8239B9FF920EEF_terseLabel_en-US" xlink:label="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_EACFA9F922926FF73F8239B9FF920EEF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carrying Amount</link:label>
    <link:label id="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_EACFA9F922926FF73F8239B9FF920EEF_label_en-US" xlink:label="lab_us-gaap_CarryingReportedAmountFairValueDisclosureMember_EACFA9F922926FF73F8239B9FF920EEF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Carrying (Reported) Amount, Fair Value Disclosure [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CarryingReportedAmountFairValueDisclosureMember" xlink:label="loc_us-gaap_CarryingReportedAmountFairValueDisclosureMember_EACFA9F922926FF73F8239B9FF920EEF" xlink:type="locator" />
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    <link:label id="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember_3DA402023F49AF59E95539B9FF9255EF_terseLabel_en-US" xlink:label="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember_3DA402023F49AF59E95539B9FF9255EF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Estimated Fair Value</link:label>
    <link:label id="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember_3DA402023F49AF59E95539B9FF9255EF_label_en-US" xlink:label="lab_us-gaap_EstimateOfFairValueFairValueDisclosureMember_3DA402023F49AF59E95539B9FF9255EF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Estimate of Fair Value, Fair Value Disclosure [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EstimateOfFairValueFairValueDisclosureMember" xlink:label="loc_us-gaap_EstimateOfFairValueFairValueDisclosureMember_3DA402023F49AF59E95539B9FF9255EF" xlink:type="locator" />
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    <link:label id="lab_ofc_OtherFixedRateDebtMember_5289751A0A2DD2BCFC5239B9FF935538_terseLabel_en-US" xlink:label="lab_ofc_OtherFixedRateDebtMember_5289751A0A2DD2BCFC5239B9FF935538" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other fixed-rate debt</link:label>
    <link:label id="lab_ofc_OtherFixedRateDebtMember_5289751A0A2DD2BCFC5239B9FF935538_label_en-US" xlink:label="lab_ofc_OtherFixedRateDebtMember_5289751A0A2DD2BCFC5239B9FF935538" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Fixed Rate Debt [Member]</link:label>
    <link:label id="lab_ofc_OtherFixedRateDebtMember_5289751A0A2DD2BCFC5239B9FF935538_documentation_en-US" xlink:label="lab_ofc_OtherFixedRateDebtMember_5289751A0A2DD2BCFC5239B9FF935538" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents all fixed-rate debt excluding the 4.25% exchangeable senior notes.</link:label>
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    <link:label id="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9A7A0643F920C4BA6D0D39B9FF930DBB_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9A7A0643F920C4BA6D0D39B9FF930DBB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Carrying amount and estimated fair value of debt</link:label>
    <link:label id="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9A7A0643F920C4BA6D0D39B9FF930DBB_label_en-US" xlink:label="lab_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9A7A0643F920C4BA6D0D39B9FF930DBB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems" xlink:label="loc_us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems_9A7A0643F920C4BA6D0D39B9FF930DBB" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LongtermDebtPercentageBearingFixedInterestAmount_F71E8A0E977A1DB1B74F39B9FF935CDA_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtPercentageBearingFixedInterestAmount_F71E8A0E977A1DB1B74F39B9FF935CDA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fixed-rate debt</link:label>
    <link:label id="lab_us-gaap_LongtermDebtPercentageBearingFixedInterestAmount_F71E8A0E977A1DB1B74F39B9FF935CDA_label_en-US" xlink:label="lab_us-gaap_LongtermDebtPercentageBearingFixedInterestAmount_F71E8A0E977A1DB1B74F39B9FF935CDA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Debt, Percentage Bearing Fixed Interest, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LongtermDebtPercentageBearingFixedInterestAmount" xlink:label="loc_us-gaap_LongtermDebtPercentageBearingFixedInterestAmount_F71E8A0E977A1DB1B74F39B9FF935CDA" xlink:type="locator" />
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    <link:label id="lab_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E_terseLabel_en-US" xlink:label="lab_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Variable-rate debt</link:label>
    <link:label id="lab_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E_label_en-US" xlink:label="lab_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Long-term Debt, Percentage Bearing Variable Interest, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LongtermDebtPercentageBearingVariableInterestAmount" xlink:label="loc_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E" xlink:to="lab_us-gaap_LongtermDebtPercentageBearingVariableInterestAmount_116DF5E7C81011F5BE5839B9FF93E65E" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeTaxDisclosureAbstract_AA5FDCA67BE50F159B5334D5A1089D3A_label_en-US" xlink:label="lab_us-gaap_IncomeTaxDisclosureAbstract_AA5FDCA67BE50F159B5334D5A1089D3A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Tax Disclosure [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxDisclosureAbstract" xlink:label="loc_us-gaap_IncomeTaxDisclosureAbstract_AA5FDCA67BE50F159B5334D5A1089D3A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeTaxDisclosureAbstract_AA5FDCA67BE50F159B5334D5A1089D3A" xlink:to="lab_us-gaap_IncomeTaxDisclosureAbstract_AA5FDCA67BE50F159B5334D5A1089D3A" xlink:type="arc" />
    <link:label id="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Components of provision for income tax</link:label>
    <link:label id="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6_label_en-US" xlink:label="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock" xlink:label="loc_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6" xlink:to="lab_us-gaap_ScheduleOfComponentsOfIncomeTaxExpenseBenefitTableTextBlock_025B1718BBBCD538115B34D5A10803E6" xlink:type="arc" />
    <link:label id="lab_us-gaap_SegmentReportingAbstract_8B6157D3B0802E7AD999C5B3FFE4B5F8_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAbstract_8B6157D3B0802E7AD999C5B3FFE4B5F8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentReportingAbstract" xlink:label="loc_us-gaap_SegmentReportingAbstract_8B6157D3B0802E7AD999C5B3FFE4B5F8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAbstract_8B6157D3B0802E7AD999C5B3FFE4B5F8" xlink:to="lab_us-gaap_SegmentReportingAbstract_8B6157D3B0802E7AD999C5B3FFE4B5F8" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C_terseLabel_en-US" xlink:label="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of primary office property segments</link:label>
    <link:label id="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C_label_en-US" xlink:label="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Primary Office Property Segments</link:label>
    <link:label id="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C_documentation_en-US" xlink:label="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of reportable primary office property segments.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfPrimaryOfficePropertySegments" xlink:label="loc_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C" xlink:to="lab_ofc_NumberOfPrimaryOfficePropertySegments_2CDB7AF075A407FE5D24C5B3FFE4BF6C" xlink:type="arc" />
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494" xlink:to="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTable_0DF6706AA110783254EEC5B3FFE45494" xlink:type="arc" />
    <link:label id="lab_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9_terseLabel_en-US" xlink:label="lab_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Statement, Business Segments [Axis]</link:label>
    <link:label id="lab_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9_label_en-US" xlink:label="lab_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Statement, Business Segments [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StatementBusinessSegmentsAxis" xlink:label="loc_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9" xlink:to="lab_us-gaap_StatementBusinessSegmentsAxis_9F4BDBCA3E8A96E21004C5B3FFE48FA9" xlink:type="arc" />
    <link:label id="lab_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment [Domain]</link:label>
    <link:label id="lab_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3_label_en-US" xlink:label="lab_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentDomain" xlink:label="loc_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3" xlink:to="lab_us-gaap_SegmentDomain_5FFCFDF03AC33ABC4249C5B3FFE46DD3" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating Segment Total</link:label>
    <link:label id="lab_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D_label_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Segments [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D" xlink:to="lab_us-gaap_OperatingSegmentsMember_3E10E023701C6D761550C5B3FFE4D58D" xlink:type="arc" />
    <link:label id="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D_terseLabel_en-US" xlink:label="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Baltimore and Washington Corridor</link:label>
    <link:label id="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D_label_en-US" xlink:label="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Baltimore and Washington Corridor [Member]</link:label>
    <link:label id="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D_documentation_en-US" xlink:label="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the Baltimore and Washington Corridor office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_BaltimoreAndWashingtonCorridorMember" xlink:label="loc_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D" xlink:to="lab_ofc_BaltimoreAndWashingtonCorridorMember_8E2E63D13CAD33185E2CC5B3FFE45C5D" xlink:type="arc" />
    <link:label id="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925_terseLabel_en-US" xlink:label="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Northern Virginia</link:label>
    <link:label id="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925_label_en-US" xlink:label="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Northern Virginia [Member]</link:label>
    <link:label id="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925_documentation_en-US" xlink:label="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents Northern Virginia office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NorthernVirginiaMember" xlink:label="loc_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925" xlink:to="lab_ofc_NorthernVirginiaMember_5E944746BAD15CC58F4AC5B3FFE58925" xlink:type="arc" />
    <link:label id="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3_terseLabel_en-US" xlink:label="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">San Antonio</link:label>
    <link:label id="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3_label_en-US" xlink:label="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">San Antonio [Member]</link:label>
    <link:label id="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3_documentation_en-US" xlink:label="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents San Antonio operating office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SanAntonioMember" xlink:label="loc_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3" xlink:to="lab_ofc_SanAntonioMember_168576BD0A51C0E82ABBC5B3FFE50CD3" xlink:type="arc" />
    <link:label id="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02_terseLabel_en-US" xlink:label="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Washington, DC - Capitol Riverfront</link:label>
    <link:label id="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02_label_en-US" xlink:label="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Washington DC Capitol Riverfront [Member]</link:label>
    <link:label id="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02_documentation_en-US" xlink:label="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the Washington, DC - Capitol Riverfront operating office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_WashingtonDcCapitolRiverfrontMember" xlink:label="loc_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02" xlink:to="lab_ofc_WashingtonDcCapitolRiverfrontMember_A55718F77E237920BE12C5B3FFE5BA02" xlink:type="arc" />
    <link:label id="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B_terseLabel_en-US" xlink:label="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">St. Mary's and King George Counties</link:label>
    <link:label id="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B_label_en-US" xlink:label="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">St Marys and King George Counties [Member]</link:label>
    <link:label id="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B_documentation_en-US" xlink:label="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents St. Mary's and King George Counties operating office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_StMarysAndKingGeorgeCountiesMember" xlink:label="loc_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B" xlink:to="lab_ofc_StMarysAndKingGeorgeCountiesMember_96DED71DDE955F2110D2C5B3FFE5957B" xlink:type="arc" />
    <link:label id="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98_terseLabel_en-US" xlink:label="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Greater Baltimore</link:label>
    <link:label id="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98_label_en-US" xlink:label="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Greater Baltimore [Member]</link:label>
    <link:label id="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98_documentation_en-US" xlink:label="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents Greater Baltimore office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_GreaterBaltimoreMember" xlink:label="loc_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98" xlink:to="lab_ofc_GreaterBaltimoreMember_24F74CC65F961966F67BC5B3FFE50C98" xlink:type="arc" />
    <link:label id="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F_terseLabel_en-US" xlink:label="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Suburban Maryland</link:label>
    <link:label id="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F_label_en-US" xlink:label="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Suburban Maryland [Member]</link:label>
    <link:label id="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F_documentation_en-US" xlink:label="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents Suburban Maryland operating office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SuburbanMarylandMember" xlink:label="loc_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F" xlink:to="lab_ofc_SuburbanMarylandMember_1D5C2D26BE40E627FD23C5B3FFE52E5F" xlink:type="arc" />
    <link:label id="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A_terseLabel_en-US" xlink:label="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Colorado Springs</link:label>
    <link:label id="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A_label_en-US" xlink:label="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Colorado Springs [Member]</link:label>
    <link:label id="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A_documentation_en-US" xlink:label="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents Colorado Springs operating office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ColoradoSpringsMember" xlink:label="loc_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A" xlink:to="lab_ofc_ColoradoSpringsMember_732DD22144723EA7EE6FC5B3FFE54B1A" xlink:type="arc" />
    <link:label id="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5_terseLabel_en-US" xlink:label="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Greater Philadelphia</link:label>
    <link:label id="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5_label_en-US" xlink:label="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Greater Philadelphia [Member]</link:label>
    <link:label id="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5_documentation_en-US" xlink:label="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents Greater Philadelphia office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_GreaterPhiladelphiaMember" xlink:label="loc_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5" xlink:to="lab_ofc_GreaterPhiladelphiaMember_05C9C82D0A890F79567FC5B3FFE5E7A5" xlink:type="arc" />
    <link:label id="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B_terseLabel_en-US" xlink:label="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B_label_en-US" xlink:label="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Segment Reporting [Member]</link:label>
    <link:label id="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B_documentation_en-US" xlink:label="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents other geographic region operating office properties, a reportable segment where real estate operations and investing activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OtherSegmentReportingMember" xlink:label="loc_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B" xlink:to="lab_ofc_OtherSegmentReportingMember_4C0660680040A66120CEC5B3FFE5011B" xlink:type="arc" />
    <link:label id="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66_terseLabel_en-US" xlink:label="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Wholesale Data Center</link:label>
    <link:label id="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66_label_en-US" xlink:label="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Wholesale Data Center [Member]</link:label>
    <link:label id="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66_documentation_en-US" xlink:label="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the wholesale data center segment of the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_WholesaleDataCenterMember" xlink:label="loc_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66" xlink:to="lab_ofc_WholesaleDataCenterMember_DBA1FA5925DEBF54F799C5B3FFE57B66" xlink:type="arc" />
    <link:label id="lab_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment financial information for real estate operations</link:label>
    <link:label id="lab_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A_label_en-US" xlink:label="lab_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Information [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentReportingInformationLineItems" xlink:label="loc_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A" xlink:to="lab_us-gaap_SegmentReportingInformationLineItems_A6B523B622EAB9E63A50C5B3FFE53E9A" xlink:type="arc" />
    <link:label id="lab_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues from real estate operations</link:label>
    <link:label id="lab_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51_label_en-US" xlink:label="lab_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Revenue, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstateRevenueNet" xlink:label="loc_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51" xlink:to="lab_us-gaap_RealEstateRevenueNet_6BB9771D8CAFF11B99C2C5B3FFE56E51" xlink:type="arc" />
    <link:label id="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4_terseLabel_en-US" xlink:label="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property operating expenses</link:label>
    <link:label id="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4_label_en-US" xlink:label="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Direct Costs of Leased and Rented Property or Equipment</link:label>
    <link:label id="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4_documentation_en-US" xlink:label="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Costs incurred and are directly related to generating revenues from leased and rented property or equipment for the reportable segment.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment" xlink:label="loc_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4" xlink:to="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_A4CBD784429121690C09C5B3FFE5A8C4" xlink:type="arc" />
    <link:label id="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F_totalLabel_en-US" xlink:label="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">NOI from real estate operations</link:label>
    <link:label id="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F_label_en-US" xlink:label="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Operating Income</link:label>
    <link:label id="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F_documentation_en-US" xlink:label="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Revenue from real estate operations for the reportable segment less property operating expenses for the reportable segment.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SegmentReportingOperatingIncome" xlink:label="loc_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F" xlink:to="lab_ofc_SegmentReportingOperatingIncome_F9E0A2AED47B54DE172EC5B3FFE5718F" xlink:type="arc" />
    <link:label id="lab_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D_terseLabel_en-US" xlink:label="lab_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Additions to long-lived assets</link:label>
    <link:label id="lab_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D_label_en-US" xlink:label="lab_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Information, Expenditures for Additions to Long-Lived Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdditionsToNoncurrentAssets" xlink:label="loc_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D" xlink:to="lab_us-gaap_AdditionsToNoncurrentAssets_D0A8604CCBD368AB0CDCC5B3FFE5C46D" xlink:type="arc" />
    <link:label id="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13_terseLabel_en-US" xlink:label="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Transfers from non-operating properties</link:label>
    <link:label id="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13_label_en-US" xlink:label="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Transfers from Non Operating Properties</link:label>
    <link:label id="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13_documentation_en-US" xlink:label="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents amounts transferred from non operating properties to reported segments during the period resulting from properties being placed into service.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SegmentReportingTransfersFromNonOperatingProperties" xlink:label="loc_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13" xlink:to="lab_ofc_SegmentReportingTransfersFromNonOperatingProperties_B63EABF8A7654C50FD97C5B3FFE5FF13" xlink:type="arc" />
    <link:label id="lab_us-gaap_Assets_C3601D6EF6EDF345795FC5B3FFE5E151_terseLabel_en-US" xlink:label="lab_us-gaap_Assets_C3601D6EF6EDF345795FC5B3FFE5E151" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Segment assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_C3601D6EF6EDF345795FC5B3FFE5E151" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets_C3601D6EF6EDF345795FC5B3FFE5E151" xlink:to="lab_us-gaap_Assets_C3601D6EF6EDF345795FC5B3FFE5E151" xlink:type="arc" />
    <link:label id="lab_us-gaap_EarningsPerShareAbstract_44C060EAB8C40AB9D81EC5EC0BC74409_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareAbstract_44C060EAB8C40AB9D81EC5EC0BC74409" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareAbstract" xlink:label="loc_us-gaap_EarningsPerShareAbstract_44C060EAB8C40AB9D81EC5EC0BC74409" xlink:type="locator" />
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    <link:label id="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_94BDEAADEE5FFE20EF7CC5EC0BC73EE9_label_en-US" xlink:label="lab_us-gaap_NetIncomeLossAvailableToCommonStockholdersDilutedAbstract_94BDEAADEE5FFE20EF7CC5EC0BC73EE9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) Available to Common Stockholders, Diluted [Abstract]</link:label>
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    <link:label id="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_D14A5DEBA56B17610E99C5EC0BC7A747_terseLabel_en-US" xlink:label="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_D14A5DEBA56B17610E99C5EC0BC7A747" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Numerator for basic EPS from continuing operations attributable to COPT common shareholders</link:label>
    <link:label id="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_D14A5DEBA56B17610E99C5EC0BC7A747_label_en-US" xlink:label="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_D14A5DEBA56B17610E99C5EC0BC7A747" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Income (Loss) from Continuing Operations, Available to Common Stockholders, Basic</link:label>
    <link:label id="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_D14A5DEBA56B17610E99C5EC0BC7A747_documentation_en-US" xlink:label="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_D14A5DEBA56B17610E99C5EC0BC7A747" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the net income from continuing operations including gain on sales of real estate, net of income taxes, after adjustments for dividends on preferred stock and income attributable to participating securities.</link:label>
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    <link:label id="lab_ofc_AmountOfDilutiveEffectOfCommonUnitsOnDilutedEarningsPerShareFromContinuingOperations_490F8075CE08DDAD29AAC5EC0BC72E7C_terseLabel_en-US" xlink:label="lab_ofc_AmountOfDilutiveEffectOfCommonUnitsOnDilutedEarningsPerShareFromContinuingOperations_490F8075CE08DDAD29AAC5EC0BC72E7C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dilutive effect of common units in the Operating Partnership on diluted EPS from continuing operations</link:label>
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    <link:label id="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive_549DCA4DDC5013B37281C5EC0BC7792C_totalLabel_en-US" xlink:label="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive_549DCA4DDC5013B37281C5EC0BC7792C" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Numerator for diluted EPS from continuing operations attributable to COPT common shareholders</link:label>
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    <link:label id="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive_549DCA4DDC5013B37281C5EC0BC7792C_documentation_en-US" xlink:label="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersDilutive_549DCA4DDC5013B37281C5EC0BC7792C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the net income from continuing operations including gain on sales of real estate, net of income taxes, after adjustments for dividends on preferred stock and income attributable to participating securities used to calculate the dilutive earnings per share.</link:label>
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    <link:label id="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_17C645A64832561C0FBFC5EC0BC74BB0_verboseLabel_en-US" xlink:label="lab_ofc_NetIncomeLossFromContinuingOperationsAvailableToCommonStockholdersBasic_17C645A64832561C0FBFC5EC0BC74BB0" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Numerator for basic EPS from continuing operations attributable to COPT common shareholders</link:label>
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    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_9CEA5984B02D6B0B2836C5EC0BC7453B_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_9CEA5984B02D6B0B2836C5EC0BC7453B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discontinued operations</link:label>
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    <link:label id="lab_ofc_NetIncomeLossAttributableToCommonStockholdersBasic_E7AEAD8721FCC70C12BEC5EC0BC7D07E_totalLabel_en-US" xlink:label="lab_ofc_NetIncomeLossAttributableToCommonStockholdersBasic_E7AEAD8721FCC70C12BEC5EC0BC7D07E" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Numerator for basic EPS on net (loss) income attributable to COPT common shareholders</link:label>
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    <link:label id="lab_ofc_NetIncomeLossAttributableToCommonStockholdersBasic_E7AEAD8721FCC70C12BEC5EC0BC7D07E_documentation_en-US" xlink:label="lab_ofc_NetIncomeLossAttributableToCommonStockholdersBasic_E7AEAD8721FCC70C12BEC5EC0BC7D07E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the net income after adjustments for gain on sales of real estate, preferred share dividends, income from continuing operations attributable to noncontrolling interests and income from continuing operations attributable to restricted shares used to calculate the dilutive earnings per share.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NetIncomeLossAttributableToCommonStockholdersBasic" xlink:label="loc_ofc_NetIncomeLossAttributableToCommonStockholdersBasic_E7AEAD8721FCC70C12BEC5EC0BC7D07E" xlink:type="locator" />
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    <link:label id="lab_ofc_AmountOfDilutiveSecuritiesCommonUnits_4680F3AF8C446A6AB104C5EC0BC87A15_terseLabel_en-US" xlink:label="lab_ofc_AmountOfDilutiveSecuritiesCommonUnits_4680F3AF8C446A6AB104C5EC0BC87A15" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dilutive effect of common units in the Operating Partnership</link:label>
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    <link:label id="lab_ofc_NetIncomeLossAttributableToCommonStockholdersDilutive_37C188846F3969E6EDF4C5EC0BC8CA78_totalLabel_en-US" xlink:label="lab_ofc_NetIncomeLossAttributableToCommonStockholdersDilutive_37C188846F3969E6EDF4C5EC0BC8CA78" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Numerator for diluted EPS on net income (loss) attributable to COPT common shareholders</link:label>
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    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_D22CCE66FE0912E1D653C5EC0BC84299_terseLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_D22CCE66FE0912E1D653C5EC0BC84299" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Denominator (all weighted averages):</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_D22CCE66FE0912E1D653C5EC0BC84299" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_D22CCE66FE0912E1D653C5EC0BC84299" xlink:to="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract_D22CCE66FE0912E1D653C5EC0BC84299" xlink:type="arc" />
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    <link:label id="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_A7A29CA8032073513BFDC5EC0BC8F01B_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_A7A29CA8032073513BFDC5EC0BC8F01B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Basic</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_WeightedAverageNumberOfSharesOutstandingBasic" xlink:label="loc_us-gaap_WeightedAverageNumberOfSharesOutstandingBasic_A7A29CA8032073513BFDC5EC0BC8F01B" xlink:type="locator" />
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    <link:label id="lab_ofc_IncrementalCommonSharesAttributableToConversionOfCommonUnits_692B86397FD9A2D3E3D8C5EC0BC819E2_documentation_en-US" xlink:label="lab_ofc_IncrementalCommonSharesAttributableToConversionOfCommonUnits_692B86397FD9A2D3E3D8C5EC0BC819E2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Additional shares included in the calculation of diluted EPS as a result of the potentially dilutive effect of convertible common units using the if-converted method.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_IncrementalCommonSharesAttributableToConversionOfCommonUnits" xlink:label="loc_ofc_IncrementalCommonSharesAttributableToConversionOfCommonUnits_692B86397FD9A2D3E3D8C5EC0BC819E2" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_848921F3095D0D293B2EC5EC0BC8D064_terseLabel_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_848921F3095D0D293B2EC5EC0BC8D064" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dilutive effect of share-based compensation awards</link:label>
    <link:label id="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_848921F3095D0D293B2EC5EC0BC8D064_label_en-US" xlink:label="lab_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_848921F3095D0D293B2EC5EC0BC8D064" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incremental Common Shares Attributable to Share-based Payment Arrangements</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements" xlink:label="loc_us-gaap_IncrementalCommonSharesAttributableToShareBasedPaymentArrangements_848921F3095D0D293B2EC5EC0BC8D064" xlink:type="locator" />
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    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E_totalLabel_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Denominator for diluted EPS</link:label>
    <link:label id="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E_label_en-US" xlink:label="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Weighted Average Number of Shares Outstanding, Diluted</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding" xlink:label="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E" xlink:to="lab_us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding_F8BBD880D2FAD3E1AAFAC5EC0BC8E28E" xlink:type="arc" />
    <link:label id="lab_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2_verboseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Basic EPS:</link:label>
    <link:label id="lab_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2_label_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Earnings Per Share, Basic [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2" xlink:to="lab_us-gaap_EarningsPerShareBasicAbstract_3B6D9CD4BBFBEDE07642C5EC0BC8F8E2" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726_verboseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Loss from continuing operations attributable to COPT common shareholders (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations, Per Basic Share</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_3531837D2BF8D79C6771C5EC0BC83726" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_8644D763785F706774AEC5EC0BC822CC_verboseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_8644D763785F706774AEC5EC0BC822CC" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Discontinued operations attributable to COPT common shareholders (in dollars per share)</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_40598F2F2665ACA08764C5EC0BC86C57" xlink:type="locator" />
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    <link:loc xlink:href="ofc-20120630.xsd#ofc_GuaranteeObligationsLiquidationProceedsWhenEntityContinuesToManagePropertiesPercentage" xlink:label="loc_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityContinuesToManagePropertiesPercentage_4CFEBA5BFEC6B64E924A391F4381C99B" xlink:type="locator" />
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    <link:label id="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95_terseLabel_en-US" xlink:label="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Recovery percentage of amount paid under the guarantee when the entity no longer manages the properties</link:label>
    <link:label id="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95_label_en-US" xlink:label="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Guarantee Obligations, Liquidation Proceeds, when Entity No Longer Manages Properties, Percentage</link:label>
    <link:label id="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95_documentation_en-US" xlink:label="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the percentage of amounts paid under the guarantees that the entity is entitled to recover from an affiliate of the general partner of the partnership pursuant to an indemnity agreement if the entity no longer manages the partnership's properties.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage" xlink:label="loc_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95" xlink:to="lab_ofc_GuaranteeObligationsLiquidationProceedsWhenEntityNoLongerManagesPropertiesPercentage_D84BEF09437C2705AB4F391F43817A95" xlink:type="arc" />
    <link:label id="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2_terseLabel_en-US" xlink:label="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum amount of office space to be developed through the joint venture (in square feet)</link:label>
    <link:label id="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2_label_en-US" xlink:label="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Developable Square Feet Maximum</link:label>
    <link:label id="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2_documentation_en-US" xlink:label="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the maximum number of square feet of office space to be developed under joint venture.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DevelopableSquareFeetMaximum" xlink:label="loc_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2" xlink:to="lab_ofc_DevelopableSquareFeetMaximum_DA2F471C2F33B1D0D028391F43827ED2" xlink:type="arc" />
    <link:label id="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C_terseLabel_en-US" xlink:label="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land available to develop office space (in acres)</link:label>
    <link:label id="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C_label_en-US" xlink:label="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Area of Land Available for Development</link:label>
    <link:label id="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C_documentation_en-US" xlink:label="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the land available to develop office space (in acres).</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AreaOfLandAvailableForDevelopment" xlink:label="loc_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C" xlink:to="lab_ofc_AreaOfLandAvailableForDevelopment_91C7125C6B46B38F9E4A391F4382D83C" xlink:type="arc" />
    <link:label id="lab_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8_terseLabel_en-US" xlink:label="lab_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Ownership (as a percent)</link:label>
    <link:label id="lab_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8_label_en-US" xlink:label="lab_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Interest Entity, Qualitative or Quantitative Information, Ownership Percentage</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityOwnershipPercentage" xlink:label="loc_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8" xlink:to="lab_us-gaap_VariableInterestEntityOwnershipPercentage_7BFA8875B8ACDC608284391F43828CF8" xlink:type="arc" />
    <link:label id="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F_terseLabel_en-US" xlink:label="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tax incremental financing obligation</link:label>
    <link:label id="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F_label_en-US" xlink:label="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tax Incremental Financing Obligation [Abstract]</link:label>
    <link:label id="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F_documentation_en-US" xlink:label="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_TaxIncrementalFinancingObligationAbstract" xlink:label="loc_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F" xlink:to="lab_ofc_TaxIncrementalFinancingObligationAbstract_67C7CAD3D0F6E83FEC89391F4382076F" xlink:type="arc" />
    <link:label id="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097_terseLabel_en-US" xlink:label="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">The amount of tax incremental financing bonds issued by Anne Arundel County, Maryland</link:label>
    <link:label id="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097_label_en-US" xlink:label="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Tax Incremental Financing Bonds Amount Issued by Anne Arundel County Maryland</link:label>
    <link:label id="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097_documentation_en-US" xlink:label="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The bond amounts issued by Anne Arundel County, Maryland to third-party investors in order to finance public improvements needed in connection with National Business Park North.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland" xlink:label="loc_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097" xlink:to="lab_ofc_TaxIncrementalFinancingBondsAmountIssuedByAnneArundelCountyMaryland_B09D63CA2C618D3DA1C3391F43828097" xlink:type="arc" />
    <link:label id="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017_terseLabel_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liability recognized with regard to tax incremental financing obligation at end of current period</link:label>
    <link:label id="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017_label_en-US" xlink:label="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Guarantor Obligations, Current Carrying Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_GuaranteeObligationsCurrentCarryingValue" xlink:label="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017" xlink:to="lab_us-gaap_GuaranteeObligationsCurrentCarryingValue_257675CB16604F46BD97391F43828017" xlink:type="arc" />
    <link:label id="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF_terseLabel_en-US" xlink:label="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Environmental Indemnity Agreement</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF_label_en-US" xlink:label="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Indemnity Agreement [Abstract]</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF_documentation_en-US" xlink:label="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EnvironmentalIndemnityAgreementAbstract" xlink:label="loc_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF" xlink:to="lab_ofc_EnvironmentalIndemnityAgreementAbstract_544B667081356214CF17391F4382F4DF" xlink:type="arc" />
    <link:label id="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910_terseLabel_en-US" xlink:label="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of lease properties which were provided environmental indemnifications</link:label>
    <link:label id="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910_label_en-US" xlink:label="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property Subject to Environmental Indemnity Lease Agreement, Number of Properties</link:label>
    <link:label id="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910_documentation_en-US" xlink:label="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of lease properties in New Jersey which were provided environmental indemnifications by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties" xlink:label="loc_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910" xlink:to="lab_ofc_PropertySubjectToEnvironmentalIndemnityLeaseAgreementNumberOfProperties_8345A70F673A57E1ECB3391F4382F910" xlink:type="arc" />
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9_terseLabel_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Environmental indemnification to the tenant against losses covered under prior owner's indemnity agreement</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9_label_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Indemnification to Tenant Against Losses Covered under Prior Owner Indemnity Agreement, Maximum</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9_documentation_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the maximum amount of environmental indemnification to the tenant against losses covered under an indemnity agreement of the prior owner of the property after the State of New Jersey declares the remediation complete.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum" xlink:label="loc_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9" xlink:to="lab_ofc_EnvironmentalIndemnificationToTenantAgainstLossesCoveredUnderPriorOwnerIndemnityAgreementMaximum_1901BF78AA6013E6A22A391F438255D9" xlink:type="arc" />
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE_terseLabel_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Length of environmental indemnification to the tenant against consequential damages at a building after the tenant's acquisition of the property (in years)</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE_label_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Indemnification to Tenant Against Consequential Damages after Acquisition of Property in Years</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE_documentation_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the length, in years, of environmental indemnification to the tenant against consequential damages at a building (e.g., business interruption) after the tenant's acquisition of such building from the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears" xlink:label="loc_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE" xlink:to="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyInYears_5A788667C9540EAABC73391F4382CCDE" xlink:type="arc" />
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyMaximum_38030800D333A8267117391F43824BE1_terseLabel_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyMaximum_38030800D333A8267117391F43824BE1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum environmental indemnification to the tenant against consequential damages after acquisition of property</link:label>
    <link:label id="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyMaximum_38030800D333A8267117391F43824BE1_label_en-US" xlink:label="lab_ofc_EnvironmentalIndemnificationToTenantAgainstConsequentialDamagesAfterAcquisitionOfPropertyMaximum_38030800D333A8267117391F43824BE1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Environmental Indemnification to Tenant Against Consequential Damages after Acquisition of Property, Maximum</link:label>
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    <link:label id="lab_ofc_ScheduleOfProjectsInDevelopmentOrHeldForFutureDevelopmentTableTextBlock_8327F6945C6B08C6B7C39C0A2DF7F53A_terseLabel_en-US" xlink:label="lab_ofc_ScheduleOfProjectsInDevelopmentOrHeldForFutureDevelopmentTableTextBlock_8327F6945C6B08C6B7C39C0A2DF7F53A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of projects in development or held for future development</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationRevenue_EFE259C877182330E89BC874B1E36316" xlink:type="locator" />
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    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890_negatedLabel_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Property operating expenses</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890_label_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Including Discontinued Operation, Property, Operating Expense</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890_documentation_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of property operating expenses attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense" xlink:label="loc_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890" xlink:to="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_CBD17525014824D7A424C874B1E3A890" xlink:type="arc" />
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8_negatedLabel_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8_label_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Including Discontinued Operation Depreciation and Amortization for Real Estate Operations</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8_documentation_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of depreciation and amortization costs attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations" xlink:label="loc_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8" xlink:to="lab_ofc_DisposalGroupIncludingDiscontinuedOperationDepreciationAndAmortizationForRealEstateOperations_7E617A3B59BFFD600982C874B1E387B8" xlink:type="arc" />
    <link:label id="lab_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459_negatedLabel_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Impairment losses</link:label>
    <link:label id="lab_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459_label_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Properties to be Disposed Discontinued Operations</link:label>
    <link:label id="lab_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459_documentation_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the aggregate impairment losses recognized during the period related to properties disposed or expected to be disposed that are included in discontinued operations.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations" xlink:label="loc_ofc_ImpairmentOfPropertiesToBeDisposedDiscontinuedOperations_CF9C43FF5898439CFEDCC874B1E33459" xlink:type="locator" />
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    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0_negatedTerseLabel_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Business development and land carry costs</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0_label_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Including Discontinued Operation Business Development and Land Carry Costs</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0_documentation_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disposal Group Including Discontinued Operation Business Development and Land Carry Costs</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts" xlink:label="loc_ofc_DisposalGroupIncludingDiscontinuedOperationBusinessDevelopmentAndLandCarryCosts_3B70FEB0F5659D4B4B6DC874B1E36BB0" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF_negatedLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Interest expense</link:label>
    <link:label id="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF_label_en-US" xlink:label="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group, Including Discontinued Operation, Interest Expense</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense" xlink:label="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF" xlink:to="lab_us-gaap_DisposalGroupIncludingDiscontinuedOperationInterestExpense_597CB3A419C07076E79EC874B1E448EF" xlink:type="arc" />
    <link:label id="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046_terseLabel_en-US" xlink:label="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain on sales of real estate</link:label>
    <link:label id="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046_label_en-US" xlink:label="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Discontinued Operation, Gain (Loss) on Sale of Real Estate</link:label>
    <link:label id="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046_documentation_en-US" xlink:label="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount, if any, of gain on sales of real estate allocated to the disposal group, including a component of the entity (discontinued operation), during the reporting period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate" xlink:label="loc_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046" xlink:to="lab_ofc_DiscontinuedOperationGainLossOnSaleOfRealEstate_AED78406B840ED4347FEC874B1E45046" xlink:type="arc" />
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0_terseLabel_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Loss on early extinguishment of debt</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0_label_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Group Including Discontinued Operation Gains (Losses) on Extinguishment of Debt</link:label>
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0_documentation_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Amount of gain or loss on early extinguishment of debt attributable to the disposal group, including a component of the entity (discontinued operation), during the reporting period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt" xlink:label="loc_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0" xlink:to="lab_ofc_DisposalGroupIncludingDiscontinuedOperationGainsLossesOnExtinguishmentOfDebt_A6338C14698F1339323BC874B1E47CB0" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_B319C48A49E14EB64FF4C874B1E42A06_totalLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_B319C48A49E14EB64FF4C874B1E42A06" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Discontinued operations</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_B319C48A49E14EB64FF4C874B1E42A06" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_B319C48A49E14EB64FF4C874B1E42A06" xlink:to="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTax_B319C48A49E14EB64FF4C874B1E42A06" xlink:type="arc" />
    <link:label id="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40_terseLabel_en-US" xlink:label="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Real Estate [Table]</link:label>
    <link:label id="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40_label_en-US" xlink:label="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Real Estate [Table]</link:label>
    <link:label id="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40_documentation_en-US" xlink:label="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Schedule that includes carrying amount of properties, accumulated depreciation and other information for real estate properties, by status.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ScheduleOfRealEstateTable" xlink:label="loc_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40" xlink:to="lab_ofc_ScheduleOfRealEstateTable_173EA7A420C89BE0C916C874B1E4CD40" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Property Disposal [Axis]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647_label_en-US" xlink:label="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Property Disposal [Axis]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information regarding disposal of operating properties aggregated according to factors such as location, number of properties and acquisition date.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertyDisposalAxis" xlink:label="loc_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647" xlink:to="lab_ofc_RealEstatePropertyDisposalAxis_BADD13BA221EEEB9105BC874B1E4E647" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Property Disposal [Domain]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD_label_en-US" xlink:label="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Property Disposal [Domain]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents operating property disposal.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertyDisposalDomain" xlink:label="loc_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD" xlink:to="lab_ofc_RealEstatePropertyDisposalDomain_F6E518110393D1C651B9C874B1E426DD" xlink:type="arc" />
    <link:label id="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD_terseLabel_en-US" xlink:label="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rutherford Business Center Portfolio</link:label>
    <link:label id="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD_label_en-US" xlink:label="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rutherford Business Center Portfolio [Member]</link:label>
    <link:label id="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD_documentation_en-US" xlink:label="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents activity related to the Rutherford Business Center Portfolio.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RutherfordBusinessCenterPortfolioMember" xlink:label="loc_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD" xlink:to="lab_ofc_RutherfordBusinessCenterPortfolioMember_C8F56DE3A6EF60FCC48CC874B1E49ADD" xlink:type="arc" />
    <link:label id="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850_terseLabel_en-US" xlink:label="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Towson Portfolio</link:label>
    <link:label id="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850_label_en-US" xlink:label="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Towson Portfolio [Member]</link:label>
    <link:label id="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850_documentation_en-US" xlink:label="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the project "Towson Portfolio" sold by the entity during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_TowsonPortfolioMember" xlink:label="loc_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850" xlink:to="lab_ofc_TowsonPortfolioMember_B65015D4F3A48FED1B71C874B1E44850" xlink:type="arc" />
    <link:label id="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009_terseLabel_en-US" xlink:label="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">White Marsh Professional Center</link:label>
    <link:label id="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009_label_en-US" xlink:label="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">White Marsh Professional Center [Member]</link:label>
    <link:label id="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009_documentation_en-US" xlink:label="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents activity related to the project White Marsh Professional Center.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_WhiteMarshProfessionalCenterMember" xlink:label="loc_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009" xlink:to="lab_ofc_WhiteMarshProfessionalCenterMember_D652E508056AA9C41A2DC874B1E44009" xlink:type="arc" />
    <link:label id="lab_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552_terseLabel_en-US" xlink:label="lab_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Major Property Class [Axis]</link:label>
    <link:label id="lab_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552_label_en-US" xlink:label="lab_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Major Property Class [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorPropertyClassAxis" xlink:label="loc_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552" xlink:to="lab_us-gaap_MajorPropertyClassAxis_14E1E5A19E64F22C9964C874B1E4E552" xlink:type="arc" />
    <link:label id="lab_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3_terseLabel_en-US" xlink:label="lab_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Major Property Class [Domain]</link:label>
    <link:label id="lab_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3_label_en-US" xlink:label="lab_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Major Property Class [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_MajorPropertyClassDomain" xlink:label="loc_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3" xlink:to="lab_us-gaap_MajorPropertyClassDomain_0F89189041C5F992BD25C874B1E4DAA3" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets Held-for-sale</link:label>
    <link:label id="lab_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7_label_en-US" xlink:label="lab_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets Held-for-sale [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsHeldForSaleMember" xlink:label="loc_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7" xlink:to="lab_us-gaap_AssetsHeldForSaleMember_EFCDC0AA62CA0F986B90C874B1E4A3B7" xlink:type="arc" />
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Properties</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PropertyPlantAndEquipmentLineItems" xlink:label="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0" xlink:to="lab_us-gaap_PropertyPlantAndEquipmentLineItems_0B3EBE266034737C01B9C874B1E489E0" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466_terseLabel_en-US" xlink:label="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of properties sold</link:label>
    <link:label id="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466_label_en-US" xlink:label="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Real Estate Properties Sold</link:label>
    <link:label id="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466_documentation_en-US" xlink:label="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of real estate properties sold during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfRealEstatePropertiesSold" xlink:label="loc_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466" xlink:to="lab_ofc_NumberOfRealEstatePropertiesSold_3EAD1B73D5CB954BBC45C874B1E4E466" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7_terseLabel_en-US" xlink:label="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of properties comprising White Marsh Professional Center</link:label>
    <link:label id="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7_label_en-US" xlink:label="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Properties Comprising Project Included in Disposition</link:label>
    <link:label id="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7_documentation_en-US" xlink:label="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of properties comprising one of the projects included in reported disposition.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition" xlink:label="loc_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7" xlink:to="lab_ofc_NumberOfPropertiesComprisingProjectIncludedInDisposition_A2CF6E3CFBCAC3275D50C874B1E466D7" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF_terseLabel_en-US" xlink:label="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of operating properties classified as held for sale</link:label>
    <link:label id="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF_label_en-US" xlink:label="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Operating Properties Classified as Held-for-sale</link:label>
    <link:label id="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF_documentation_en-US" xlink:label="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of operating properties classified as held for sale as of reporting date.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale" xlink:label="loc_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF" xlink:to="lab_ofc_NumberOfOperatingPropertiesClassifiedAsHeldForSale_D3BCFE5297C09A77091EC874B1E46EDF" xlink:type="arc" />
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyNet_B82C226AEBA392806241C874B1E4AA9F_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyNet_B82C226AEBA392806241C874B1E4AA9F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Properties, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstateInvestmentPropertyNet" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyNet_B82C226AEBA392806241C874B1E4AA9F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentPropertyNet_B82C226AEBA392806241C874B1E4AA9F" xlink:to="lab_us-gaap_RealEstateInvestmentPropertyNet_B82C226AEBA392806241C874B1E4AA9F" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred leasing costs, net</link:label>
    <link:label id="lab_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A_label_en-US" xlink:label="lab_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Costs, Leasing, Net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredCostsLeasingNet" xlink:label="loc_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A" xlink:to="lab_us-gaap_DeferredCostsLeasingNet_ED7F77B55A05F40051D1C874B1E5728A" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3_terseLabel_en-US" xlink:label="lab_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Lease incentives</link:label>
    <link:label id="lab_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3_label_en-US" xlink:label="lab_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Incentive to Lessee</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncentiveToLessee" xlink:label="loc_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3" xlink:to="lab_us-gaap_IncentiveToLessee_937ED27CD7FB0AB77CBFC874B1E503D3" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_75184DD12A3153EFBBB0C874B1E5668E_totalLabel_en-US" xlink:label="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_75184DD12A3153EFBBB0C874B1E5668E" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Assets held for sale</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation" xlink:label="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_75184DD12A3153EFBBB0C874B1E5668E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_75184DD12A3153EFBBB0C874B1E5668E" xlink:to="lab_us-gaap_AssetsOfDisposalGroupIncludingDiscontinuedOperation_75184DD12A3153EFBBB0C874B1E5668E" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties Status [Axis]</link:label>
    <link:label id="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140_label_en-US" xlink:label="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties Status [Axis]</link:label>
    <link:label id="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Information by status of the property.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertiesStatusAxis" xlink:label="loc_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140" xlink:to="lab_ofc_RealEstatePropertiesStatusAxis_4EBCBA0C833EF46532BC5D6A685E4140" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertiesStatusDomain_29609731699ADADD6CA75D6A685EE2B4_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertiesStatusDomain_29609731699ADADD6CA75D6A685EE2B4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties Status [Domain]</link:label>
    <link:label id="lab_ofc_RealEstatePropertiesStatusDomain_29609731699ADADD6CA75D6A685EE2B4_label_en-US" xlink:label="lab_ofc_RealEstatePropertiesStatusDomain_29609731699ADADD6CA75D6A685EE2B4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties Status [Domain]</link:label>
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    <link:label id="lab_ofc_OperatingPropertiesMember_FB4C2CCE54DA022D761E5D6A685E312A_terseLabel_en-US" xlink:label="lab_ofc_OperatingPropertiesMember_FB4C2CCE54DA022D761E5D6A685E312A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating properties, net</link:label>
    <link:label id="lab_ofc_OperatingPropertiesMember_FB4C2CCE54DA022D761E5D6A685E312A_label_en-US" xlink:label="lab_ofc_OperatingPropertiesMember_FB4C2CCE54DA022D761E5D6A685E312A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Properties [Member]</link:label>
    <link:label id="lab_ofc_OperatingPropertiesMember_FB4C2CCE54DA022D761E5D6A685E312A_documentation_en-US" xlink:label="lab_ofc_OperatingPropertiesMember_FB4C2CCE54DA022D761E5D6A685E312A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to operating properties of the entity, including discontinued operations.</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_D6147883D909362E339B5D6A685E98D3_terseLabel_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_D6147883D909362E339B5D6A685E98D3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment by Type [Axis]</link:label>
    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_D6147883D909362E339B5D6A685E98D3_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentByTypeAxis_D6147883D909362E339B5D6A685E98D3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment by Type [Axis]</link:label>
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    <link:label id="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_248B55D48065346F08FD5D6A685EE8F8_label_en-US" xlink:label="lab_us-gaap_PropertyPlantAndEquipmentTypeDomain_248B55D48065346F08FD5D6A685EE8F8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Property, Plant and Equipment, Type [Domain]</link:label>
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    <link:label id="lab_us-gaap_LandMember_721F3206BFD710FCE7055D6A685E3A9E_verboseLabel_en-US" xlink:label="lab_us-gaap_LandMember_721F3206BFD710FCE7055D6A685E3A9E" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Land</link:label>
    <link:label id="lab_us-gaap_LandMember_721F3206BFD710FCE7055D6A685E3A9E_label_en-US" xlink:label="lab_us-gaap_LandMember_721F3206BFD710FCE7055D6A685E3A9E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land [Member]</link:label>
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    <link:label id="lab_us-gaap_BuildingAndBuildingImprovementsMember_69B1083D11212143DB045D6A685E27CB_terseLabel_en-US" xlink:label="lab_us-gaap_BuildingAndBuildingImprovementsMember_69B1083D11212143DB045D6A685E27CB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Buildings and improvements</link:label>
    <link:label id="lab_us-gaap_BuildingAndBuildingImprovementsMember_69B1083D11212143DB045D6A685E27CB_label_en-US" xlink:label="lab_us-gaap_BuildingAndBuildingImprovementsMember_69B1083D11212143DB045D6A685E27CB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Building and Building Improvements [Member]</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BuildingAndBuildingImprovementsMember_69B1083D11212143DB045D6A685E27CB" xlink:to="lab_us-gaap_BuildingAndBuildingImprovementsMember_69B1083D11212143DB045D6A685E27CB" xlink:type="arc" />
    <link:label id="lab_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B_positiveLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B" xlink:role="http://www.xbrl.org/2003/role/positiveLabel" xlink:type="resource" xml:lang="en-US">Properties</link:label>
    <link:label id="lab_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B_label_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstatePropertiesLineItems" xlink:label="loc_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B" xlink:to="lab_us-gaap_RealEstatePropertiesLineItems_533ED69F4EE1538E89DD5D6A685E159B" xlink:type="arc" />
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gross</link:label>
    <link:label id="lab_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99_label_en-US" xlink:label="lab_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate, Gross</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstateGrossAtCarryingValue" xlink:label="loc_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99" xlink:to="lab_us-gaap_RealEstateGrossAtCarryingValue_6F0AE081BFA1C6A7229E5D6A685EEF99" xlink:type="arc" />
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C_negatedLabel_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Less: accumulated depreciation</link:label>
    <link:label id="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C_label_en-US" xlink:label="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Investment Property, Accumulated Depreciation</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation" xlink:label="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C" xlink:to="lab_us-gaap_RealEstateInvestmentPropertyAccumulatedDepreciation_A306775D87B2D082B91A5D6A685E296C" xlink:type="arc" />
    <link:label id="lab_us-gaap_RentalProperties_7E62C5B3A10C9601D2DF5D6A685E59E4_totalLabel_en-US" xlink:label="lab_us-gaap_RentalProperties_7E62C5B3A10C9601D2DF5D6A685E59E4" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Operating properties, net</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RentalProperties" xlink:label="loc_us-gaap_RentalProperties_7E62C5B3A10C9601D2DF5D6A685E59E4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RentalProperties_7E62C5B3A10C9601D2DF5D6A685E59E4" xlink:to="lab_us-gaap_RentalProperties_7E62C5B3A10C9601D2DF5D6A685E59E4" xlink:type="arc" />
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_4D4216A9DF993886E8103509082EFC7E_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_4D4216A9DF993886E8103509082EFC7E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of segment financial information for real estate operations</link:label>
    <link:label id="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_4D4216A9DF993886E8103509082EFC7E_label_en-US" xlink:label="lab_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_4D4216A9DF993886E8103509082EFC7E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Segment Reporting Information, by Segment [Table Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock" xlink:label="loc_us-gaap_ScheduleOfSegmentReportingInformationBySegmentTextBlock_4D4216A9DF993886E8103509082EFC7E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock_B8217A7DAA69D9D1EE743509082F38AA_terseLabel_en-US" xlink:label="lab_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock_B8217A7DAA69D9D1EE743509082F38AA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of reconciliation of segment revenues to total revenues</link:label>
    <link:label id="lab_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock_B8217A7DAA69D9D1EE743509082F38AA_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfRevenueFromSegmentsToConsolidatedTextBlock_B8217A7DAA69D9D1EE743509082F38AA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reconciliation of Revenue from Segments to Consolidated [Table Text Block]</link:label>
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    <link:label id="lab_ofc_ReconciliationOfPropertyOperatingExpensesFromSegmentsToConsolidatedTextBlock_355E16C534E028D28BFD3509082FD519_terseLabel_en-US" xlink:label="lab_ofc_ReconciliationOfPropertyOperatingExpensesFromSegmentsToConsolidatedTextBlock_355E16C534E028D28BFD3509082FD519" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of reconciliation of segment property operating expenses to total property operating expenses</link:label>
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    <link:label id="lab_ofc_ScheduleOfNetOperatingIncomeFromSegmentsFromServiceOperationsTableTextBlock_50A9161A2BF3E1633DA93509082F4371_terseLabel_en-US" xlink:label="lab_ofc_ScheduleOfNetOperatingIncomeFromSegmentsFromServiceOperationsTableTextBlock_50A9161A2BF3E1633DA93509082F4371" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of computation of net operating income from service operations</link:label>
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    <link:label id="lab_ofc_RealEstatePropertyClassificationDomain_DBD3922150993922545DBF5CEE189D68_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertyClassificationDomain_DBD3922150993922545DBF5CEE189D68" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents classification of real estate properties.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertyClassificationDomain" xlink:label="loc_ofc_RealEstatePropertyClassificationDomain_DBD3922150993922545DBF5CEE189D68" xlink:type="locator" />
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    <link:label id="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA_terseLabel_en-US" xlink:label="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-operating properties</link:label>
    <link:label id="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA_label_en-US" xlink:label="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-operating Properties [Member]</link:label>
    <link:label id="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA_documentation_en-US" xlink:label="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to non-operating properties of the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NonOperatingPropertiesMember" xlink:label="loc_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA" xlink:to="lab_ofc_NonOperatingPropertiesMember_757052D5AC6BC84D945FBF5CEE1856EA" xlink:type="arc" />
    <link:label id="lab_ofc_AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts_1C06C8A60D0AE83D30BEBF5CEE186D88_terseLabel_en-US" xlink:label="lab_ofc_AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts_1C06C8A60D0AE83D30BEBF5CEE186D88" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment losses</link:label>
    <link:label id="lab_ofc_AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts_1C06C8A60D0AE83D30BEBF5CEE186D88_label_en-US" xlink:label="lab_ofc_AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts_1C06C8A60D0AE83D30BEBF5CEE186D88" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Asset Impairment Charges, Continuing and Noncontinuing Operations Including Exit Costs</link:label>
    <link:label id="lab_ofc_AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts_1C06C8A60D0AE83D30BEBF5CEE186D88_documentation_en-US" xlink:label="lab_ofc_AssetImpairmentChargesContinuingAndNoncontinuingOperationsIncludingExitCosts_1C06C8A60D0AE83D30BEBF5CEE186D88" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The charge against earnings from continuing and noncontinuing operations resulting from the aggregate write down of all assets from their carrying value to their fair value.</link:label>
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    <link:label id="lab_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_2700A81CB709C0469686350908133761_label_en-US" xlink:label="lab_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_2700A81CB709C0469686350908133761" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Reconciliation of Assets from Segment to Consolidated [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable" xlink:label="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_2700A81CB709C0469686350908133761" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_2700A81CB709C0469686350908133761" xlink:to="lab_us-gaap_ReconciliationOfAssetsFromSegmentToConsolidatedTable_2700A81CB709C0469686350908133761" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingSegmentsMember_7F70B10AF082176C419A35090813197B_verboseLabel_en-US" xlink:label="lab_us-gaap_OperatingSegmentsMember_7F70B10AF082176C419A35090813197B" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Segment assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingSegmentsMember" xlink:label="loc_us-gaap_OperatingSegmentsMember_7F70B10AF082176C419A35090813197B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OperatingSegmentsMember_7F70B10AF082176C419A35090813197B" xlink:to="lab_us-gaap_OperatingSegmentsMember_7F70B10AF082176C419A35090813197B" xlink:type="arc" />
    <link:label id="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066_terseLabel_en-US" xlink:label="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Non-operating property assets</link:label>
    <link:label id="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066_label_en-US" xlink:label="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Non-Operating Property Assets [Member]</link:label>
    <link:label id="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066_documentation_en-US" xlink:label="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents amounts pertaining to non-operating properties.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NonOperatingPropertyAssetsMember" xlink:label="loc_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066" xlink:to="lab_ofc_NonOperatingPropertyAssetsMember_953F9317DC01F05D07B3350908137066" xlink:type="arc" />
    <link:label id="lab_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E_terseLabel_en-US" xlink:label="lab_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other</link:label>
    <link:label id="lab_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E_label_en-US" xlink:label="lab_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Unallocated Amount to Segment [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_UnallocatedAmountToSegmentMember" xlink:label="loc_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E" xlink:to="lab_us-gaap_UnallocatedAmountToSegmentMember_80EA8FAE393BA29D884A350908135A0E" xlink:type="arc" />
    <link:label id="lab_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5_terseLabel_en-US" xlink:label="lab_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reconciliation of segment assets to total assets</link:label>
    <link:label id="lab_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5_label_en-US" xlink:label="lab_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting, Asset Reconciling Item [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SegmentReportingAssetReconcilingItemLineItems" xlink:label="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5" xlink:to="lab_us-gaap_SegmentReportingAssetReconcilingItemLineItems_F51EDA4766E784479E0A350908140DB5" xlink:type="arc" />
    <link:label id="lab_us-gaap_Assets_6D9F39AD3A72433B7C95350908141260_verboseLabel_en-US" xlink:label="lab_us-gaap_Assets_6D9F39AD3A72433B7C95350908141260" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Assets" xlink:label="loc_us-gaap_Assets_6D9F39AD3A72433B7C95350908141260" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Assets_6D9F39AD3A72433B7C95350908141260" xlink:to="lab_us-gaap_Assets_6D9F39AD3A72433B7C95350908141260" xlink:type="arc" />
    <link:label id="lab_us-gaap_AccountingPoliciesAbstract_CBAFFF963A7A84DA559DC874B3171FFF_label_en-US" xlink:label="lab_us-gaap_AccountingPoliciesAbstract_CBAFFF963A7A84DA559DC874B3171FFF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Accounting Policies [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AccountingPoliciesAbstract" xlink:label="loc_us-gaap_AccountingPoliciesAbstract_CBAFFF963A7A84DA559DC874B3171FFF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AccountingPoliciesAbstract_CBAFFF963A7A84DA559DC874B3171FFF" xlink:to="lab_us-gaap_AccountingPoliciesAbstract_CBAFFF963A7A84DA559DC874B3171FFF" xlink:type="arc" />
    <link:label id="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7_terseLabel_en-US" xlink:label="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Basis of Presentation</link:label>
    <link:label id="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7_label_en-US" xlink:label="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Basis of Presentation [Policy Text Block]</link:label>
    <link:label id="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7_documentation_en-US" xlink:label="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disclosure of accounting policy for the basis of presentation of financial statements.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_BasisOfPresentationPolicyTextBlock" xlink:label="loc_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7" xlink:to="lab_ofc_BasisOfPresentationPolicyTextBlock_6AC694C660F73DD503C2C874B317F4D7" xlink:type="arc" />
    <link:label id="lab_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A_terseLabel_en-US" xlink:label="lab_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reclassifications</link:label>
    <link:label id="lab_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A_label_en-US" xlink:label="lab_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Comparability of Prior Year Financial Data, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ComparabilityOfPriorYearFinancialData" xlink:label="loc_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A" xlink:to="lab_us-gaap_ComparabilityOfPriorYearFinancialData_08F4B6DC7B14A04204E9C874B317857A" xlink:type="arc" />
    <link:label id="lab_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003_terseLabel_en-US" xlink:label="lab_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Recent Accounting Pronouncements</link:label>
    <link:label id="lab_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003_label_en-US" xlink:label="lab_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
    <link:label id="lab_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003_documentation_en-US" xlink:label="lab_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">New Accounting Pronouncements, Policy [Policy Text Block]</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NewAccountingPronouncementsPolicyPolicyTextBlock" xlink:label="loc_ofc_NewAccountingPronouncementsPolicyPolicyTextBlock_885F7B11C63B8289035EC874B3176003" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ImpairmentOrDisposalOfLongLivedIntangibleAssetsImpairmentPolicy_E7C711EFC547F10DB3D6C874B317AA37_terseLabel_en-US" xlink:label="lab_us-gaap_ImpairmentOrDisposalOfLongLivedIntangibleAssetsImpairmentPolicy_E7C711EFC547F10DB3D6C874B317AA37" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairments</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ImpairmentOrDisposalOfLongLivedIntangibleAssetsImpairmentPolicy" xlink:label="loc_us-gaap_ImpairmentOrDisposalOfLongLivedIntangibleAssetsImpairmentPolicy_E7C711EFC547F10DB3D6C874B317AA37" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ImpairmentOrDisposalOfLongLivedIntangibleAssetsImpairmentPolicy_E7C711EFC547F10DB3D6C874B317AA37" xlink:to="lab_us-gaap_ImpairmentOrDisposalOfLongLivedIntangibleAssetsImpairmentPolicy_E7C711EFC547F10DB3D6C874B317AA37" xlink:type="arc" />
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_BE8493A46C10D27A5F7FC5EBC7729028_terseLabel_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_BE8493A46C10D27A5F7FC5EBC7729028" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Accounts receivable, allowance for doubtful accounts</link:label>
    <link:label id="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_BE8493A46C10D27A5F7FC5EBC7729028_label_en-US" xlink:label="lab_us-gaap_AllowanceForDoubtfulAccountsReceivable_BE8493A46C10D27A5F7FC5EBC7729028" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Allowance for Doubtful Accounts Receivable</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AllowanceForDoubtfulAccountsReceivable" xlink:label="loc_us-gaap_AllowanceForDoubtfulAccountsReceivable_BE8493A46C10D27A5F7FC5EBC7729028" xlink:type="locator" />
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    <link:label id="lab_ofc_KeywHoldingCorporationMember_6DCEFF2F27A4341B4A22B4EE3457CE1F_terseLabel_en-US" xlink:label="lab_ofc_KeywHoldingCorporationMember_6DCEFF2F27A4341B4A22B4EE3457CE1F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">KEYW Holding Corporation</link:label>
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    <link:label id="lab_ofc_KeywHoldingCorporationMember_6DCEFF2F27A4341B4A22B4EE3457CE1F_documentation_en-US" xlink:label="lab_ofc_KeywHoldingCorporationMember_6DCEFF2F27A4341B4A22B4EE3457CE1F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents KEYW Holding Corporation, trading security investee of the entity.</link:label>
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    <link:label id="lab_us-gaap_InvestmentOwnedBalanceShares_624CC1111D177CB74A0FB4EE34573DD5_terseLabel_en-US" xlink:label="lab_us-gaap_InvestmentOwnedBalanceShares_624CC1111D177CB74A0FB4EE34573DD5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of shares owned in investee (in shares)</link:label>
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    <link:label id="lab_ofc_TradingSecurityOwnershipPercentage_E581C8F9C03E180A3302B4EE34574A94_documentation_en-US" xlink:label="lab_ofc_TradingSecurityOwnershipPercentage_E581C8F9C03E180A3302B4EE34574A94" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The percentage of ownership of common stock or equity participation in the investee accounted for as a trading security</link:label>
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    <link:label id="lab_ofc_TradingSecurityInvestmentSaleOfShares_7AC0E88EAFD4E7132881B4EE3457C979_terseLabel_en-US" xlink:label="lab_ofc_TradingSecurityInvestmentSaleOfShares_7AC0E88EAFD4E7132881B4EE3457C979" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Amount of sale of owned shares</link:label>
    <link:label id="lab_ofc_TradingSecurityInvestmentSaleOfShares_7AC0E88EAFD4E7132881B4EE3457C979_label_en-US" xlink:label="lab_ofc_TradingSecurityInvestmentSaleOfShares_7AC0E88EAFD4E7132881B4EE3457C979" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Trading Security Investment Sale of Shares</link:label>
    <link:label id="lab_ofc_TradingSecurityInvestmentSaleOfShares_7AC0E88EAFD4E7132881B4EE3457C979_documentation_en-US" xlink:label="lab_ofc_TradingSecurityInvestmentSaleOfShares_7AC0E88EAFD4E7132881B4EE3457C979" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of shares of common stock owned in the investee accounted for as a trading security that were sold.</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PrepaidExpenseCurrentAndNoncurrent" xlink:label="loc_us-gaap_PrepaidExpenseCurrentAndNoncurrent_89FA14E90BC06449C642968FBC14899B" xlink:type="locator" />
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    <link:label id="lab_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B_terseLabel_en-US" xlink:label="lab_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Subsequent Event [Line Items]</link:label>
    <link:label id="lab_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B_label_en-US" xlink:label="lab_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Subsequent Event [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SubsequentEventLineItems" xlink:label="loc_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B" xlink:to="lab_us-gaap_SubsequentEventLineItems_E9C00671096AAD481806C874B1A2353B" xlink:type="arc" />
    <link:label id="lab_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90_terseLabel_en-US" xlink:label="lab_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Notional Amount</link:label>
    <link:label id="lab_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90_label_en-US" xlink:label="lab_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Notional Amount of Interest Rate Cash Flow Hedge Derivatives</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives" xlink:label="loc_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90" xlink:to="lab_us-gaap_NotionalAmountOfInterestRateCashFlowHedgeDerivatives_BAE17A1CC61D3E740541C874B1A29F90" xlink:type="arc" />
    <link:label id="lab_us-gaap_DerivativeFixedInterestRate_CCBBF74544B99D353CECC874B1A2E4ED_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeFixedInterestRate_CCBBF74544B99D353CECC874B1A2E4ED" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fixed rate (as a percent)</link:label>
    <link:label id="lab_us-gaap_DerivativeFixedInterestRate_CCBBF74544B99D353CECC874B1A2E4ED_label_en-US" xlink:label="lab_us-gaap_DerivativeFixedInterestRate_CCBBF74544B99D353CECC874B1A2E4ED" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Fixed Interest Rate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeFixedInterestRate" xlink:label="loc_us-gaap_DerivativeFixedInterestRate_CCBBF74544B99D353CECC874B1A2E4ED" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Floating rate index</link:label>
    <link:label id="lab_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11_label_en-US" xlink:label="lab_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative, Description of Variable Rate Basis</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DerivativeDescriptionOfVariableRateBasis" xlink:label="loc_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11" xlink:to="lab_us-gaap_DerivativeDescriptionOfVariableRateBasis_1865F876BFFBE578DE36C874B1A29C11" xlink:type="arc" />
    <link:label id="lab_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F_terseLabel_en-US" xlink:label="lab_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Square footage of real estate properties (in square feet)</link:label>
    <link:label id="lab_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F_label_en-US" xlink:label="lab_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Square Footage of Real Estate Property</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SquareFootageOfRealEstateProperty" xlink:label="loc_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F" xlink:to="lab_us-gaap_SquareFootageOfRealEstateProperty_84F109C59871D6640AE6C874B1A2E67F" xlink:type="arc" />
    <link:label id="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801_terseLabel_en-US" xlink:label="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Acquired property, percentage leased</link:label>
    <link:label id="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801_label_en-US" xlink:label="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acquired Property, Percentage Leased</link:label>
    <link:label id="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801_documentation_en-US" xlink:label="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The percentage of acquired property that is leased at the time of acquisition, expressed as a percent.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AcquiredPropertyPercentageLeased" xlink:label="loc_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801" xlink:to="lab_ofc_AcquiredPropertyPercentageLeased_7EA3DD45AC5F9764E6EEC874B1A24801" xlink:type="arc" />
    <link:label id="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D_terseLabel_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Cost of acquired property</link:label>
    <link:label id="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D_label_en-US" xlink:label="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Business Acquisition, Cost of Acquired Entity, Purchase Price</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice" xlink:label="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D" xlink:to="lab_us-gaap_BusinessAcquisitionCostOfAcquiredEntityPurchasePrice_FC3DCCECD9AFC2986A2EC874B1A2633D" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6_terseLabel_en-US" xlink:label="lab_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of real estate operating properties sold</link:label>
    <link:label id="lab_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6_label_en-US" xlink:label="lab_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Real Estate Operating Properties Sold</link:label>
    <link:label id="lab_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6_documentation_en-US" xlink:label="lab_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represent the number of operating real estate properties sold during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfRealEstateOperatingPropertiesSold" xlink:label="loc_ofc_NumberOfRealEstateOperatingPropertiesSold_9649A7C1EF73E26A2B0CC874B1A256E6" xlink:type="locator" />
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    <link:label id="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46_verboseLabel_en-US" xlink:label="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Acres of land parcel sold</link:label>
    <link:label id="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46_label_en-US" xlink:label="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acres of Real Estate Property</link:label>
    <link:label id="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46_documentation_en-US" xlink:label="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the area of land parcels in acres.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AcresOfRealEstateProperty" xlink:label="loc_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46" xlink:to="lab_ofc_AcresOfRealEstateProperty_4D889576B0FFA2FA0A99C874B1A2FB46" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607_terseLabel_en-US" xlink:label="lab_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sales price of properties sold</link:label>
    <link:label id="lab_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607_label_en-US" xlink:label="lab_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Aggregate Sales Price</link:label>
    <link:label id="lab_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607_documentation_en-US" xlink:label="lab_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the aggregate sales price excluding closing costs, of real estate properties sold by the entity during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstateAggregateSalesPrice" xlink:label="loc_ofc_RealEstateAggregateSalesPrice_C4F6EB77CCA2C3C90D7AC874B1A2A607" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PreferredStockLiquidationPreference_43DF75C1ADD9742F3E5EC874B1A2003D_verboseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockLiquidationPreference_43DF75C1ADD9742F3E5EC874B1A2003D" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Preferred stock, liquidation preference per share</link:label>
    <link:label id="lab_us-gaap_PreferredStockLiquidationPreference_43DF75C1ADD9742F3E5EC874B1A2003D_label_en-US" xlink:label="lab_us-gaap_PreferredStockLiquidationPreference_43DF75C1ADD9742F3E5EC874B1A2003D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Preferred Stock, Liquidation Preference Per Share</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PreferredStockLiquidationPreference" xlink:label="loc_us-gaap_PreferredStockLiquidationPreference_43DF75C1ADD9742F3E5EC874B1A2003D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_PreferredStockValue_CEC6BDDC2B3C4E484D59C874B1A2D00B_terseLabel_en-US" xlink:label="lab_us-gaap_PreferredStockValue_CEC6BDDC2B3C4E484D59C874B1A2D00B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Preferred stock, liquidation preference value in aggregate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PreferredStockValue" xlink:label="loc_us-gaap_PreferredStockValue_CEC6BDDC2B3C4E484D59C874B1A2D00B" xlink:type="locator" />
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    <link:label id="lab_us-gaap_BasisOfPresentationAndSignificantAccountingPoliciesTextBlock_631A22D003EAAABFFA92578DFB177CEC_terseLabel_en-US" xlink:label="lab_us-gaap_BasisOfPresentationAndSignificantAccountingPoliciesTextBlock_631A22D003EAAABFFA92578DFB177CEC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Basis of Presentation and Significant Accounting Policies [Text Block]</link:label>
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    <link:label id="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_1D3AEFCB28BD342523689A34CE7BCC16_label_en-US" xlink:label="lab_us-gaap_OrganizationConsolidationAndPresentationOfFinancialStatementsAbstract_1D3AEFCB28BD342523689A34CE7BCC16" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Organization, Consolidation and Presentation of Financial Statements [Abstract]</link:label>
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    <link:label id="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE_terseLabel_en-US" xlink:label="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Operating office properties</link:label>
    <link:label id="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE_label_en-US" xlink:label="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Office Properties [Member]</link:label>
    <link:label id="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE_documentation_en-US" xlink:label="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents operating office properties owned by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OperatingOfficePropertiesMember" xlink:label="loc_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE" xlink:to="lab_ofc_OperatingOfficePropertiesMember_4EBDCE86EE0FA08E2AE49A34CE7B15EE" xlink:type="arc" />
    <link:label id="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340_terseLabel_en-US" xlink:label="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Office properties under construction or redevelopment</link:label>
    <link:label id="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340_label_en-US" xlink:label="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Office Properties Under Construction or Redevelopment [Member]</link:label>
    <link:label id="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340_documentation_en-US" xlink:label="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents office properties under construction or redevelopment owned by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember" xlink:label="loc_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340" xlink:to="lab_ofc_OfficePropertiesUnderConstructionOrRedevelopmentMember_5B79694E7FC0BAA3A12F9A34CE7B2340" xlink:type="arc" />
    <link:label id="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE_terseLabel_en-US" xlink:label="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Office properties under construction or redevelopment which are partially operational</link:label>
    <link:label id="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE_label_en-US" xlink:label="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Partially Operational Properties [Member]</link:label>
    <link:label id="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE_documentation_en-US" xlink:label="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents office properties under construction or redevelopment which are owned by the entity and which are partially operational.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PartiallyOperationalPropertiesMember" xlink:label="loc_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE" xlink:to="lab_ofc_PartiallyOperationalPropertiesMember_43EE14178B228A9324869A34CE7B35DE" xlink:type="arc" />
    <link:label id="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5_terseLabel_en-US" xlink:label="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Land held or under pre-construction</link:label>
    <link:label id="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5_label_en-US" xlink:label="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Land Held or under Preconstruction [Member]</link:label>
    <link:label id="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5_documentation_en-US" xlink:label="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents land held by the entity or underdoing pre-construction activities.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_LandHeldOrUnderPreconstructionMember" xlink:label="loc_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5" xlink:to="lab_ofc_LandHeldOrUnderPreconstructionMember_32AE64E13F1EF65D6B359A34CE7BB6B5" xlink:type="arc" />
    <link:label id="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839_terseLabel_en-US" xlink:label="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Partially operational, wholesale data center</link:label>
    <link:label id="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839_label_en-US" xlink:label="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Partially Operational Wholesale Data Center [Member]</link:label>
    <link:label id="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839_documentation_en-US" xlink:label="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents partially operational, wholesale data center owned by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PartiallyOperationalWholesaleDataCenterMember" xlink:label="loc_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839" xlink:to="lab_ofc_PartiallyOperationalWholesaleDataCenterMember_A37AF2BF9A7E80E120DF9A34CE7BF839" xlink:type="arc" />
    <link:label id="lab_us-gaap_RealEstatePropertiesLineItems_55465E178DF9B9F0E4839A34CE7BEF7D_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesLineItems_55465E178DF9B9F0E4839A34CE7BEF7D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investments in real estate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstatePropertiesLineItems" xlink:label="loc_us-gaap_RealEstatePropertiesLineItems_55465E178DF9B9F0E4839A34CE7BEF7D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_55465E178DF9B9F0E4839A34CE7BEF7D" xlink:to="lab_us-gaap_RealEstatePropertiesLineItems_55465E178DF9B9F0E4839A34CE7BEF7D" xlink:type="arc" />
    <link:label id="lab_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1_terseLabel_en-US" xlink:label="lab_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of real estate properties</link:label>
    <link:label id="lab_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1_label_en-US" xlink:label="lab_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Real Estate Properties</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_NumberOfRealEstateProperties" xlink:label="loc_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1" xlink:to="lab_us-gaap_NumberOfRealEstateProperties_EA8A06903C7BD300A6759A34CE7C5AC1" xlink:type="arc" />
    <link:label id="lab_ofc_AcresOfRealEstateProperty_3E88E1F4FAB741F7B4399A34CE7C751E_terseLabel_en-US" xlink:label="lab_ofc_AcresOfRealEstateProperty_3E88E1F4FAB741F7B4399A34CE7C751E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Area of land held or under pre-construction (in acres)</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AcresOfRealEstateProperty" xlink:label="loc_ofc_AcresOfRealEstateProperty_3E88E1F4FAB741F7B4399A34CE7C751E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AcresOfRealEstateProperty_3E88E1F4FAB741F7B4399A34CE7C751E" xlink:to="lab_ofc_AcresOfRealEstateProperty_3E88E1F4FAB741F7B4399A34CE7C751E" xlink:type="arc" />
    <link:label id="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60_terseLabel_en-US" xlink:label="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Area of land parcels controlled but not owned (in acres)</link:label>
    <link:label id="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60_label_en-US" xlink:label="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Acres of Real Estate Property Controlled but Not Owned</link:label>
    <link:label id="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60_documentation_en-US" xlink:label="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the area of land parcels held or under pre-construction that is controlled but not owned.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AcresOfRealEstatePropertyControlledButNotOwned" xlink:label="loc_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60" xlink:to="lab_ofc_AcresOfRealEstatePropertyControlledButNotOwned_EDE205DFAB820E50E1659A34CE7CEE60" xlink:type="arc" />
    <link:label id="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267_terseLabel_en-US" xlink:label="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Developable square footage of real estate properties (in square feet)</link:label>
    <link:label id="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267_label_en-US" xlink:label="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Developable Square Feet</link:label>
    <link:label id="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267_documentation_en-US" xlink:label="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of square feet into which a land parcel is potentially developable.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DevelopableSquareFeet" xlink:label="loc_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267" xlink:to="lab_ofc_DevelopableSquareFeet_E26167111DA85FCB46F89A34CE7CB267" xlink:type="arc" />
    <link:label id="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23_terseLabel_en-US" xlink:label="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">The expected stabilization critical load after completion of development (in megawatts)</link:label>
    <link:label id="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23_label_en-US" xlink:label="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Expected Stabilization Critical Load</link:label>
    <link:label id="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23_documentation_en-US" xlink:label="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the expected stabilization critical load after completion of development of the property. Critical load is the amount of megawatts of power made available for the exclusive use tenants in the property.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ExpectedStabilizationCriticalLoad" xlink:label="loc_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23" xlink:to="lab_ofc_ExpectedStabilizationCriticalLoad_9A2F1173630D0F11B2AF9A34CE7CEA23" xlink:type="arc" />
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementsByShareBasedPaymentAwardTable_64EAFA6E23FA6ADB5698BB2505414D25" xlink:type="arc" />
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3_label_en-US" xlink:label="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Share-based Compensation Arrangement by Share-based Payment Award, Award Type and Plan Name [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis" xlink:label="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3" xlink:to="lab_us-gaap_ScheduleOfShareBasedCompensationArrangementByShareBasedPaymentAwardAwardTypeAndPlanNameAxis_5F0F0E2A9F97F3700B5EBB2505411EA3" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain]</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangements by Share-based Payment Award, Award Type and Plan Name [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementsByShareBasedPaymentAwardAwardTypeAndPlanNameDomain_9ABA677FFD8F5544CA38BB25054183AF" xlink:type="arc" />
    <link:label id="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4_terseLabel_en-US" xlink:label="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance share units</link:label>
    <link:label id="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4_label_en-US" xlink:label="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Performance Share Units [Member]</link:label>
    <link:label id="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4_documentation_en-US" xlink:label="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents performance share unit awards granted by the entity to its employees. The actual awards earned by employees from these grants are a function of the entity's total shareholder return performance over a defined performance period in comparison to a peer group of companies.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PerformanceShareUnitsMember" xlink:label="loc_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4" xlink:to="lab_ofc_PerformanceShareUnitsMember_7ACCA36D55D883C8081FBB2505412EF4" xlink:type="arc" />
    <link:label id="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903_terseLabel_en-US" xlink:label="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Restricted shares</link:label>
    <link:label id="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903_label_en-US" xlink:label="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Restricted Shares [Member]</link:label>
    <link:label id="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903_documentation_en-US" xlink:label="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Restricted stock are shares of stock for which sale is contractually or governmentally restricted for a given period of time.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RestrictedSharesMember" xlink:label="loc_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903" xlink:to="lab_ofc_RestrictedSharesMember_7BEF5D117D80B51CA19FBB250541A903" xlink:type="arc" />
    <link:label id="lab_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6_terseLabel_en-US" xlink:label="lab_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Options</link:label>
    <link:label id="lab_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6_label_en-US" xlink:label="lab_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Option [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockOptionMember" xlink:label="loc_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6" xlink:to="lab_us-gaap_StockOptionMember_909C8C4EAD5181D5F92CBB25054168A6" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-Based Compensation</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardLineItems_08D0075A8A33D3AE9752BB2505412DDD" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Potential earned PSUs payout for defined levels of performance under awards</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Earned Performance Share Units, Payout Percentage [Abstract]</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract" xlink:label="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C" xlink:to="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEarnedPerformanceShareUnitsPayoutPercentageAbstract_F6F4388FB65364EE0BE5BB2505417D9C" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Earned PSUs payout (as a percent of PSUs granted) on 75th or greater percentile rank</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award of Earned, Performance Share Units, Payout Percentage Based on Percentile Rank Greater than or Equals to 75</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the earned performance share units payout, as a percentage of performance share units granted, if the entity's total shareholder return relative to a peer group of companies ranks at the 75th percentile or greater.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75" xlink:label="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812" xlink:to="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankGreaterThanOrEqualsTo75_0BAA8CF4218EDA2130E5BB2505423812" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Earned PSUs payout (as a percent of PSUs granted) on 50th percentile rank</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award of Earned, Performance Share Units, Payout Percentage Based on Percentile Rank Equals to 50</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the earned performance share units payout, as a percentage of performance share units granted, if the entity's total shareholder return relative to a peer group of companies ranks at the 50th percentile.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50" xlink:label="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363" xlink:to="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo50_387B6A64772FFAE8D5BCBB2505424363" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Earned PSUs payout (as a percent of PSUs granted) on 25th percentile rank</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award of Earned, Performance Share Units, Payout Percentage Based on Percentile Rank Equals to 25</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the earned performance share units payout, as a percentage of performance share units granted, if the entity's total shareholder return relative to a peer group of companies ranks at the 25th percentile.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25" xlink:label="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1" xlink:to="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankEqualsTo25_6E914D834A795B25EE0DBB2505429CA1" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Performance share units granted on percentile rank below 25th (as a percent)</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award of Earned, Performance Share Units, Payout Percentage Based on Percentile Rank Less than 25</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the earned performance share units payout percentage based on percentile rank below 25.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25" xlink:label="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317" xlink:to="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardOfEarnedPerformanceShareUnitsPayoutPercentageBasedOnPercentileRankLessThan25_E7B176CC020208A65678BB250542C317" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A_terseLabel_en-US" xlink:label="lab_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">The number of percentile ranks to fall between to earn interpolated PSUs between such percentile ranks, conditioned on the percentile rank exceeding 25%</link:label>
    <link:label id="lab_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A_label_en-US" xlink:label="lab_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Percentile Ranks to Fall Between to Earn Interpolated PSU</link:label>
    <link:label id="lab_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A_documentation_en-US" xlink:label="lab_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The number of percentile ranks to fall between to earn interpolated PSUs between such percentile ranks, conditioned on the percentile rank exceeding 25%.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu" xlink:label="loc_ofc_NumberOfPercentileRanksToFallBetweenToEarnInterpolatedPsu_D2F973370A632107C1E1BB250542B09A" xlink:type="locator" />
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_5C68D9965DC06DCA482FBB250542B713" xlink:to="lab_us-gaap_StockIssuedDuringPeriodSharesStockOptionsExercised_5C68D9965DC06DCA482FBB250542B713" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exercise price range, options exercised (in dollars per share)</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Shares Authorized under Stock Option Plans, Exercise Price of Exercised Options</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The exercise price for purposes of disclosing shares exercised under stock option awards on all stock option plans.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions" xlink:label="loc_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0" xlink:to="lab_ofc_ShareBasedCompensationSharesAuthorizedUnderStockOptionPlansExercisePriceOfExercisedOptions_BECE8CC1625D7DD8112CBB25054248B0" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value (in dollars)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue_7A7FD1E13AC5C9ADEEF8BB2505432D6F" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698_terseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other Share-based Compensation Additional Disclosures</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsAdditionalDisclosuresAbstract_78BAD79C9FC14256720BBB2505439698" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Restricted common shares, forfeiture restrictions lapsed (in shares)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriod_EC23E2BD3F140937312DBB250543B830" xlink:type="arc" />
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1_verboseLabel_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Weighted average grant date fair value of restricted common share, forfeiture restrictions lapsed (in dollars per share)</link:label>
    <link:label id="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1_label_en-US" xlink:label="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue" xlink:label="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1" xlink:to="lab_us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodWeightedAverageGrantDateFairValue_B755E96B2DC271D23E50BB25054300F1" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate intrinsic value of restricted common shares, forfeiture restrictions lapsed</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation, Arrangement by Share-based Payment Award Equity Instruments other than Options Vested in Period Total Intrinsic Value</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The total intrinsic value of equity-based payment equity instruments, excluding stock (or unit) options, that vested during the reporting period as calculated by applying the disclosed pricing methodology.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue" xlink:label="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD" xlink:to="lab_ofc_ShareBasedCompensationArrangementByShareBasedPaymentAwardEquityInstrumentsOtherThanOptionsVestedInPeriodTotalIntrinsicValue_ABEA996E8343712DE34DBB25054310DD" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties Dispositions [Table]</link:label>
    <link:label id="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629_label_en-US" xlink:label="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties Dispositions [Table]</link:label>
    <link:label id="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Information related to dispositions of properties.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertiesDispositionsTable" xlink:label="loc_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629" xlink:to="lab_ofc_RealEstatePropertiesDispositionsTable_791CD548ED84D0BECF5EB4F894842629" xlink:type="arc" />
    <link:label id="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368_terseLabel_en-US" xlink:label="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">White Marsh Portfolio</link:label>
    <link:label id="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368_label_en-US" xlink:label="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">White Marsh Portfolio [Member]</link:label>
    <link:label id="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368_documentation_en-US" xlink:label="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the project "White Marsh Portfolio" sold by the entity during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_WhiteMarshPortfolioMember" xlink:label="loc_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368" xlink:to="lab_ofc_WhiteMarshPortfolioMember_F7A539988976BD58B43BB4F89484F368" xlink:type="arc" />
    <link:label id="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95_terseLabel_en-US" xlink:label="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">1101 Sentry Gateway</link:label>
    <link:label id="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95_label_en-US" xlink:label="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sentry Gateway 1101 [Member]</link:label>
    <link:label id="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95_documentation_en-US" xlink:label="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the project "1101 Sentry Gateway" sold by the entity during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SentryGateway1101Member" xlink:label="loc_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95" xlink:to="lab_ofc_SentryGateway1101Member_54A598D47117806A2528B4F89484BC95" xlink:type="arc" />
    <link:label id="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C_terseLabel_en-US" xlink:label="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">222 and 224 Schilling Circle</link:label>
    <link:label id="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C_label_en-US" xlink:label="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schilling Circle 222 and 224 [Member]</link:label>
    <link:label id="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C_documentation_en-US" xlink:label="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the project "222 and 224 Schilling Circle" sold by the entity during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SchillingCircle222And224Member" xlink:label="loc_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C" xlink:to="lab_ofc_SchillingCircle222And224Member_AB21A3E74C99277B29AAB4F89484C28C" xlink:type="arc" />
    <link:label id="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587_terseLabel_en-US" xlink:label="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">15 and 45 West Gude Drive</link:label>
    <link:label id="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587_label_en-US" xlink:label="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number 15 and 45 West Gude Drive [Member]</link:label>
    <link:label id="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587_documentation_en-US" xlink:label="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the information pertaining to 15 and 45 West Gude Drive, an office property owned by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_Number15And45WestGudeDriveMember" xlink:label="loc_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587" xlink:to="lab_ofc_Number15And45WestGudeDriveMember_72D6273F96C4A7420AECB4F894840587" xlink:type="arc" />
    <link:label id="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C_terseLabel_en-US" xlink:label="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">11800 Tech Road</link:label>
    <link:label id="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C_label_en-US" xlink:label="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number 11800 Tech Road [Member]</link:label>
    <link:label id="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C_documentation_en-US" xlink:label="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the information pertaining to 11800 Tech Road, an office property owned by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_Number11800TechRoadMember" xlink:label="loc_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C" xlink:to="lab_ofc_Number11800TechRoadMember_05FAC1E286937DC2BBBFB4F89484376C" xlink:type="arc" />
    <link:label id="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08_terseLabel_en-US" xlink:label="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Dispositions</link:label>
    <link:label id="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08_label_en-US" xlink:label="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Significant Disposals [Line Items]</link:label>
    <link:label id="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08_documentation_en-US" xlink:label="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SignificantDisposalsLineItems" xlink:label="loc_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08" xlink:to="lab_ofc_SignificantDisposalsLineItems_F08D07F001726B5650FCB4F894847E08" xlink:type="arc" />
    <link:label id="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64_terseLabel_en-US" xlink:label="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of Buildings</link:label>
    <link:label id="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64_label_en-US" xlink:label="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Properties Sold</link:label>
    <link:label id="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64_documentation_en-US" xlink:label="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of properties sold during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfPropertiesSold" xlink:label="loc_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64" xlink:to="lab_ofc_NumberOfPropertiesSold_818E59D9B03D5C4CF70AB4F894841D64" xlink:type="arc" />
    <link:label id="lab_us-gaap_SquareFootageOfRealEstateProperty_395899541AE2D32BE34FB4F894848846_verboseLabel_en-US" xlink:label="lab_us-gaap_SquareFootageOfRealEstateProperty_395899541AE2D32BE34FB4F894848846" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total Rentable Square Feet</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_SquareFootageOfRealEstateProperty" xlink:label="loc_us-gaap_SquareFootageOfRealEstateProperty_395899541AE2D32BE34FB4F894848846" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_SquareFootageOfRealEstateProperty_395899541AE2D32BE34FB4F894848846" xlink:to="lab_us-gaap_SquareFootageOfRealEstateProperty_395899541AE2D32BE34FB4F894848846" xlink:type="arc" />
    <link:label id="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C_terseLabel_en-US" xlink:label="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Price of Operating Properties</link:label>
    <link:label id="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C_label_en-US" xlink:label="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sales Price of Operating Properties Sold</link:label>
    <link:label id="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C_documentation_en-US" xlink:label="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the total sales price of operating properties sold during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SalesPriceOfOperatingPropertiesSold" xlink:label="loc_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C" xlink:to="lab_ofc_SalesPriceOfOperatingPropertiesSold_9583C41C3D1E943251D1B4F894842A7C" xlink:type="arc" />
    <link:label id="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E_terseLabel_en-US" xlink:label="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Sale Price of Non-operating Properties</link:label>
    <link:label id="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E_label_en-US" xlink:label="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Sales Price of Non-operating Properties Sold</link:label>
    <link:label id="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E_documentation_en-US" xlink:label="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the total sales price of non-operating properties sold during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SalesPriceOfNonOperatingPropertiesSold" xlink:label="loc_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E" xlink:to="lab_ofc_SalesPriceOfNonOperatingPropertiesSold_57C26026A6679586FA27B4F89485391E" xlink:type="arc" />
    <link:label id="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9_terseLabel_en-US" xlink:label="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Gain on Sale</link:label>
    <link:label id="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9_label_en-US" xlink:label="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Gain on Sale of Properties Sold</link:label>
    <link:label id="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9_documentation_en-US" xlink:label="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the total gain recognized on properties sold during the period.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_GainOnSaleOfPropertiesSold" xlink:label="loc_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9" xlink:to="lab_ofc_GainOnSaleOfPropertiesSold_BA86BF674DE51B1A16E9B4F894854AC9" xlink:type="arc" />
    <link:label id="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB_terseLabel_en-US" xlink:label="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Disposals and Impairment Losses</link:label>
    <link:label id="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB_label_en-US" xlink:label="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment Losses [Abstract]</link:label>
    <link:label id="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB_documentation_en-US" xlink:label="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ImpairmentLossesAbstract" xlink:label="loc_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB" xlink:to="lab_ofc_ImpairmentLossesAbstract_618DA5B0133AE6105341B4F8948584EB" xlink:type="arc" />
    <link:label id="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239_terseLabel_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate net impairment losses recognized in connection with disposition plan</link:label>
    <link:label id="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239_label_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Properties in Connection with Disposition Plan Aggregate</link:label>
    <link:label id="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239_documentation_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the aggregate net impairment loss recognized during the period in connection with disposition plan, including amounts in continuing and discontinued operations.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate" xlink:label="loc_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239" xlink:to="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanAggregate_6849CCAACA6A8033C8A9B4F894855239" xlink:type="arc" />
    <link:label id="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26_terseLabel_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Aggregate net impairment losses recognized in discontinued operation in connection with disposition plan</link:label>
    <link:label id="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26_label_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment of Properties in Connection with Disposition Plan in Discontinued Operations</link:label>
    <link:label id="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26_documentation_en-US" xlink:label="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the aggregate net impairment loss recognized during the period in connection with disposition plan that is included in discontinued operations.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations" xlink:label="loc_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26" xlink:to="lab_ofc_ImpairmentOfPropertiesInConnectionWithDispositionPlanInDiscontinuedOperations_992310EDCF38083A076BB4F89485AA26" xlink:type="arc" />
    <link:label id="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9_terseLabel_en-US" xlink:label="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Exit cost included in net impairment losses recognized in connection with disposition plan</link:label>
    <link:label id="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9_label_en-US" xlink:label="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Exit Costs Included in Impairment Losses in Connection with Disposition Plan</link:label>
    <link:label id="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9_documentation_en-US" xlink:label="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the exit costs included in aggregate net impairment loss recognized during the period in connection with disposition plan.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan" xlink:label="loc_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9" xlink:to="lab_ofc_ExitCostsIncludedInImpairmentLossesInConnectionWithDispositionPlan_FC27C28324621303C31BB4F8948530B9" xlink:type="arc" />
    <link:label id="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD_terseLabel_en-US" xlink:label="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Net impairment losses on expected disposition of additional property</link:label>
    <link:label id="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD_label_en-US" xlink:label="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Impairment on Expected Dispostion of Additional Property</link:label>
    <link:label id="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD_documentation_en-US" xlink:label="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the impairment loss recognized during the period related to expected disposition of additional property, including amounts in continuing and discontinued operations.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty" xlink:label="loc_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD" xlink:to="lab_ofc_ImpairmentOnExpectedDispostionOfAdditionalProperty_EA50886BE79DA36C5B79B4F8948516CD" xlink:type="arc" />
    <link:label id="lab_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C_label_en-US" xlink:label="lab_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Document and Entity Information [Abstract]</link:label>
    <link:label id="lab_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C_documentation_en-US" xlink:label="lab_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">-- None. No documentation exists for this element. --</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DocumentAndEntityInformationAbstract" xlink:label="loc_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C" xlink:to="lab_ofc_DocumentAndEntityInformationAbstract_5FB305DDAD9A0C94556B900B95D1005C" xlink:type="arc" />
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    <link:label id="lab_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04_label_en-US" xlink:label="lab_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Marketable Securities [Member]</link:label>
    <link:label id="lab_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04_documentation_en-US" xlink:label="lab_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents other marketable securities not otherwise specified in taxonomy.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OtherMarketableSecuritiesMember" xlink:label="loc_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04" xlink:to="lab_ofc_OtherMarketableSecuritiesMember_682FBC0F16628FCB03A2BF5CEE3DFB04" xlink:type="arc" />
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets and liabilities measured at fair value on a recurring basis</link:label>
    <link:label id="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D_label_en-US" xlink:label="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems" xlink:label="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D" xlink:to="lab_us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringAndNonrecurringBasisLineItems_525CCE611986DE30EB1CBF5CEE3E284D" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets:</link:label>
    <link:label id="lab_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390_label_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets, Fair Value Disclosure [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsFairValueDisclosureAbstract" xlink:label="loc_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390" xlink:to="lab_us-gaap_AssetsFairValueDisclosureAbstract_560E9FF21BEBF76A90C2BF5CEE3E3390" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Marketable securities in deferred compensation plan</link:label>
    <link:label id="lab_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3_label_en-US" xlink:label="lab_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Compensation Plan Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredCompensationPlanAssets" xlink:label="loc_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3" xlink:to="lab_us-gaap_DeferredCompensationPlanAssets_A5C25AEC25155D9DCE3DBF5CEE3ED2F3" xlink:type="arc" />
    <link:label id="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB_terseLabel_en-US" xlink:label="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common stocks</link:label>
    <link:label id="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB_label_en-US" xlink:label="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Investment in Common Stock Fair Value, Disclosure</link:label>
    <link:label id="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB_documentation_en-US" xlink:label="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the aggregate of the investment in common stock of other entities reported on the balance sheet at the end of the period measured at fair value by the entity, excluding amounts held under deferred compensation arrangements.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InvestmentInCommonStockFairValueDisclosure" xlink:label="loc_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB" xlink:to="lab_ofc_InvestmentInCommonStockFairValueDisclosure_5DFD187D87C0025215C1BF5CEE3EF8DB" xlink:type="arc" />
    <link:label id="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2_terseLabel_en-US" xlink:label="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Warrants to purchase common shares in KEYW</link:label>
    <link:label id="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2_label_en-US" xlink:label="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Warrants Fair Value Disclosure</link:label>
    <link:label id="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2_documentation_en-US" xlink:label="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Fair value as of the balance sheet date of warrants, which includes warrants to purchase common stock in publicly traded corporations.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_WarrantsFairValueDisclosure" xlink:label="loc_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2" xlink:to="lab_ofc_WarrantsFairValueDisclosure_86ECD84407A7884D3784BF5CEE3E4CC2" xlink:type="arc" />
    <link:label id="lab_us-gaap_AssetsFairValueDisclosure_7A2ED8DAB2BAACCB0215BF5CEE3EEC7C_terseLabel_en-US" xlink:label="lab_us-gaap_AssetsFairValueDisclosure_7A2ED8DAB2BAACCB0215BF5CEE3EEC7C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AssetsFairValueDisclosure" xlink:label="loc_us-gaap_AssetsFairValueDisclosure_7A2ED8DAB2BAACCB0215BF5CEE3EEC7C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AssetsFairValueDisclosure_7A2ED8DAB2BAACCB0215BF5CEE3EEC7C" xlink:to="lab_us-gaap_AssetsFairValueDisclosure_7A2ED8DAB2BAACCB0215BF5CEE3EEC7C" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities:</link:label>
    <link:label id="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E_label_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities, Fair Value Disclosure [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosureAbstract" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E" xlink:to="lab_us-gaap_LiabilitiesFairValueDisclosureAbstract_75CAE8706E7BA3F3866BBF5CEE3EEC3E" xlink:type="arc" />
    <link:label id="lab_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F_terseLabel_en-US" xlink:label="lab_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Deferred compensation plan liability</link:label>
    <link:label id="lab_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F_label_en-US" xlink:label="lab_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Deferred Compensation Liability, Current and Noncurrent</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent" xlink:label="loc_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F" xlink:to="lab_us-gaap_DeferredCompensationLiabilityCurrentAndNoncurrent_11838E195F7A0F1E36EDBF5CEE3E402F" xlink:type="arc" />
    <link:label id="lab_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E_terseLabel_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities</link:label>
    <link:label id="lab_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E_label_en-US" xlink:label="lab_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Liabilities, Fair Value Disclosure</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_LiabilitiesFairValueDisclosure" xlink:label="loc_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E" xlink:to="lab_us-gaap_LiabilitiesFairValueDisclosure_82CE2BD18E4117389BF7BF5CEE3E3E5E" xlink:type="arc" />
    <link:label id="lab_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Fair value measurement on a nonrecurring basis</link:label>
    <link:label id="lab_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421_label_en-US" xlink:label="lab_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Measurements, Nonrecurring [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueMeasurementsNonrecurringMember" xlink:label="loc_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421" xlink:to="lab_us-gaap_FairValueMeasurementsNonrecurringMember_20CDC66F089D1B675C27BF5CB6606421" xlink:type="arc" />
    <link:label id="lab_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1_terseLabel_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Significant Unobservable Inputs (Level 3)</link:label>
    <link:label id="lab_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1_label_en-US" xlink:label="lab_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Fair Value, Inputs, Level 3 [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_FairValueInputsLevel3Member" xlink:label="loc_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1" xlink:to="lab_us-gaap_FairValueInputsLevel3Member_8F156DBD6E7E371AB19EBF5CB66085D1" xlink:type="arc" />
    <link:label id="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8_terseLabel_en-US" xlink:label="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets by Type [Axis]</link:label>
    <link:label id="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8_label_en-US" xlink:label="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets by Type [Axis]</link:label>
    <link:label id="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8_documentation_en-US" xlink:label="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the type of assets.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AssetsByTypeAxis" xlink:label="loc_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8" xlink:to="lab_ofc_AssetsByTypeAxis_0772AFB0556D135969BABF5CB66049B8" xlink:type="arc" />
    <link:label id="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305_terseLabel_en-US" xlink:label="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Assets by Name [Domain]</link:label>
    <link:label id="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305_label_en-US" xlink:label="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Assets by Name [Domain]</link:label>
    <link:label id="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305_documentation_en-US" xlink:label="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The name of the entity's assets.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_AssetsByNameDomain" xlink:label="loc_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305" xlink:to="lab_ofc_AssetsByNameDomain_27D8F168BBD35D65283EBF5CB6609305" xlink:type="arc" />
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    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40_negatedLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Costs associated with common shares issued to the public</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments to Additional Paid in Capital, Stock Issued, Issuance Costs</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalStockIssuedIssuanceCosts_6C1BA33B0114A1ED05CDC422B564BF40" xlink:type="arc" />
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF_negatedLabel_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Exercise of share options (180,464 and 12,667 shares in 2011 and 2012, respectively)</link:label>
    <link:label id="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF_label_en-US" xlink:label="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Issued During Period, Value, Stock Options Exercised</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised" xlink:label="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF" xlink:to="lab_us-gaap_StockIssuedDuringPeriodValueStockOptionsExercised_5A4C4632A295C895FB22C422B56420FF" xlink:type="arc" />
    <link:label id="lab_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791_terseLabel_en-US" xlink:label="lab_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Share-based compensation</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791_label_en-US" xlink:label="lab_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Share-based Compensation Recognized</link:label>
    <link:label id="lab_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791_documentation_en-US" xlink:label="lab_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This element represents the amount of equity adjustments from recognized share-based compensation during the period, that is, the amount recognized as expense in the income statement (or as asset if compensation is capitalized).</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ShareBasedCompensationRecognized" xlink:label="loc_ofc_ShareBasedCompensationRecognized_70EC0738C113B16D7D9AC422B5644791" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0_negatedLabel_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Restricted common share redemptions (107,442 and 133,081 shares in 2011 and 2012, respectively)</link:label>
    <link:label id="lab_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0_label_en-US" xlink:label="lab_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Stock Repurchased During Period, Value</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockRepurchasedDuringPeriodValue" xlink:label="loc_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0" xlink:to="lab_us-gaap_StockRepurchasedDuringPeriodValue_558D99B0AFD94262D459C422B5649BB0" xlink:type="arc" />
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB_terseLabel_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustments to noncontrolling interests resulting from changes in ownership of Operating Partnership by COPT</link:label>
    <link:label id="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB_label_en-US" xlink:label="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Adjustments to Additional Paid in Capital, Reallocation of Noncontrolling Interest</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest" xlink:label="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB" xlink:to="lab_us-gaap_AdjustmentsToAdditionalPaidInCapitalReallocationOfMinorityInterest_A94329890DD51ABCFCBBC422B56473BB" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease_EDB7CAF88B4D45558F14C422B5640161_terseLabel_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease_EDB7CAF88B4D45558F14C422B5640161" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Adjustments related to derivatives designated as cash flow hedges</link:label>
    <link:label id="lab_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease_EDB7CAF88B4D45558F14C422B5640161_label_en-US" xlink:label="lab_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease_EDB7CAF88B4D45558F14C422B5640161" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease" xlink:label="loc_us-gaap_OtherComprehensiveIncomeDerivativesQualifyingAsHedgesNetOfTaxPeriodIncreaseDecrease_EDB7CAF88B4D45558F14C422B5640161" xlink:type="locator" />
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    <link:label id="lab_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1_negatedLabel_en-US" xlink:label="lab_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Dividends</link:label>
    <link:label id="lab_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1_label_en-US" xlink:label="lab_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dividends</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_Dividends" xlink:label="loc_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1" xlink:to="lab_us-gaap_Dividends_61E3F43DA57D06693ED8C422B564CDC1" xlink:type="arc" />
    <link:label id="lab_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675_negatedLabel_en-US" xlink:label="lab_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Distributions to owners of common and preferred units in the Operating Partnership</link:label>
    <link:label id="lab_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675_label_en-US" xlink:label="lab_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minority Interest (Decrease) from Distributions to Operating Partnership Noncontrolling Interest Holders</link:label>
    <link:label id="lab_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675_documentation_en-US" xlink:label="lab_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Decrease in noncontrolling interest balance from payment of distributions to noncontrolling interest holders in the Operating Partnership.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders" xlink:label="loc_ofc_MinorityInterestDecreaseFromDistributionsToOperatingPartnershipNoncontrollingInterestHolders_86E45D72554DF163E3F8C422B5644675" xlink:type="locator" />
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    <link:label id="lab_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411_negatedLabel_en-US" xlink:label="lab_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Contributions from noncontrolling interests in other consolidated entities</link:label>
    <link:label id="lab_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411_label_en-US" xlink:label="lab_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minority Interest Increase from Contributions Including Joint Ventures</link:label>
    <link:label id="lab_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411_documentation_en-US" xlink:label="lab_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Increase in noncontrolling interest balance as a result of contributions from equity interests owned by noncontrolling shareholders, partners, or other equity holders in joint ventures included in the entity's consolidated financial statements.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures" xlink:label="loc_ofc_MinorityInterestIncreaseFromContributionsIncludingJointVentures_D61C12CD1141AB6A3DC8C422B5641411" xlink:type="locator" />
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    <link:label id="lab_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127_negatedLabel_en-US" xlink:label="lab_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Distributions to noncontrolling interests in other consolidated entities</link:label>
    <link:label id="lab_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127_label_en-US" xlink:label="lab_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Minority Interest (Decrease) from Distributions Including Joint Ventures</link:label>
    <link:label id="lab_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127_documentation_en-US" xlink:label="lab_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Decrease in noncontrolling interest balance as a result of distributions to equity interests owned by noncontrolling shareholders, partners, or other equity holders in joint ventures included in the entity's consolidated financial statements.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures" xlink:label="loc_ofc_MinorityInterestDecreaseFromDistributionsIncludingJointVentures_6F8AEE3FFCF69E006C7DC422B564E127" xlink:type="locator" />
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    <link:label id="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_27B5F14411D65E9C15ABC422B5641EF5_periodEndLabel_en-US" xlink:label="lab_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_27B5F14411D65E9C15ABC422B5641EF5" xlink:role="http://www.xbrl.org/2003/role/periodEndLabel" xlink:type="resource" xml:lang="en-US">Balance</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest" xlink:label="loc_us-gaap_StockholdersEquityIncludingPortionAttributableToNoncontrollingInterest_27B5F14411D65E9C15ABC422B5641EF5" xlink:type="locator" />
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    <link:label id="lab_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85_terseLabel_en-US" xlink:label="lab_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate, Joint Ventures [Table]</link:label>
    <link:label id="lab_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85_label_en-US" xlink:label="lab_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate, Joint Ventures [Table]</link:label>
    <link:label id="lab_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85_documentation_en-US" xlink:label="lab_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Tabular disclosure of information related to unconsolidated and consolidated real estate joint ventures.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstateJointVenturesTable" xlink:label="loc_ofc_RealEstateJointVenturesTable_909E664F018C5B56239EB4EB9E51CF85" xlink:type="locator" />
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    <link:label id="lab_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59_terseLabel_en-US" xlink:label="lab_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Legal Entity [Axis]</link:label>
    <link:label id="lab_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59_label_en-US" xlink:label="lab_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Legal Entity [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_LegalEntityAxis" xlink:label="loc_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59" xlink:to="lab_dei_LegalEntityAxis_3A7CDF42B9E4095F5C81B4EB9E516E59" xlink:type="arc" />
    <link:label id="lab_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D_terseLabel_en-US" xlink:label="lab_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Entity [Domain]</link:label>
    <link:label id="lab_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D_label_en-US" xlink:label="lab_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Entity [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.sec.gov/dei/2011/dei-2011-01-31.xsd#dei_EntityDomain" xlink:label="loc_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D" xlink:to="lab_dei_EntityDomain_C9D707EF89B3956FDFB3B4EB9E51694D" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Unconsolidated real estate joint ventures</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investments [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentsMember" xlink:label="loc_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E" xlink:to="lab_us-gaap_EquityMethodInvestmentsMember_3CDE2E2A7CC39E64C4A7B4EB9E51B22E" xlink:type="arc" />
    <link:label id="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03_terseLabel_en-US" xlink:label="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">LW Redstone Company, LLC</link:label>
    <link:label id="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03_label_en-US" xlink:label="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">LW Redstone Company LLC [Member]</link:label>
    <link:label id="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03_documentation_en-US" xlink:label="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the investment in L W Redstone Company, LLC, a consolidated joint venture.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_LwRedstoneCompanyLlcMember" xlink:label="loc_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03" xlink:to="lab_ofc_LwRedstoneCompanyLlcMember_7535EFFB45A85C3FED3FB4EB9E514B03" xlink:type="arc" />
    <link:label id="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E_terseLabel_en-US" xlink:label="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">M Square Associates, LLC</link:label>
    <link:label id="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E_label_en-US" xlink:label="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">M Square Associates LLC [Member]</link:label>
    <link:label id="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E_documentation_en-US" xlink:label="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the investment in M Square Associates, LLC, a consolidated joint venture.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MSquareAssociatesLlcMember" xlink:label="loc_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E" xlink:to="lab_ofc_MSquareAssociatesLlcMember_C67887DDA567E125D9F5B4EB9E51EA7E" xlink:type="arc" />
    <link:label id="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F_terseLabel_en-US" xlink:label="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Arundel Preserve 5, LLC</link:label>
    <link:label id="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F_label_en-US" xlink:label="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Arundel Preserve LLC [Member]</link:label>
    <link:label id="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F_documentation_en-US" xlink:label="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the investment in Arundel Preserve 5, LLC, a consolidated joint venture.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ArundelPreserveLlcMember" xlink:label="loc_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F" xlink:to="lab_ofc_ArundelPreserveLlcMember_5DE7AC527CAFC3423C35B4EB9E51497F" xlink:type="arc" />
    <link:label id="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91_terseLabel_en-US" xlink:label="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">COPT-FD Indian Head, LLC</link:label>
    <link:label id="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91_label_en-US" xlink:label="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">COPT-FD Indian Head LLC [Member]</link:label>
    <link:label id="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91_documentation_en-US" xlink:label="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the investment in COPT-FD Indian Head, LLC, a consolidated joint venture.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_CoptFdIndianHeadLlcMember" xlink:label="loc_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91" xlink:to="lab_ofc_CoptFdIndianHeadLlcMember_E78F0EFFD2562FCD9B93B4EB9E519D91" xlink:type="arc" />
    <link:label id="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E_terseLabel_en-US" xlink:label="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">MOR Forbes 2 LLC</link:label>
    <link:label id="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E_label_en-US" xlink:label="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">MOR Forbes 2 LLC [Member]</link:label>
    <link:label id="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E_documentation_en-US" xlink:label="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the investment in MOR Forbes 2, LLC, a consolidated joint venture.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_MorForbes2LlcMember" xlink:label="loc_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E" xlink:to="lab_ofc_MorForbes2LlcMember_F043D4F44A8DF731B9D0B4EB9E51884E" xlink:type="arc" />
    <link:label id="lab_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98_terseLabel_en-US" xlink:label="lab_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Consolidated real estate joint ventures</link:label>
    <link:label id="lab_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98_label_en-US" xlink:label="lab_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Interest Entity, Primary Beneficiary, Aggregated Disclosure [Member]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember" xlink:label="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98" xlink:to="lab_us-gaap_VariableInterestEntityPrimaryBeneficiaryAggregatedDisclosureMember_4FD4FD165C27F328D05FB4EB9E51FA98" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374_terseLabel_en-US" xlink:label="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Investments in real estate joint ventures</link:label>
    <link:label id="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374_label_en-US" xlink:label="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Joint Venture [Line Items]</link:label>
    <link:label id="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374_documentation_en-US" xlink:label="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstateJointVentureLineItems" xlink:label="loc_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374" xlink:to="lab_ofc_RealEstateJointVentureLineItems_AD3C88C206C69645DFF2B4EB9E518374" xlink:type="arc" />
    <link:label id="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A_terseLabel_en-US" xlink:label="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of unconsolidated real estate joint ventures in which the entity has an interest</link:label>
    <link:label id="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A_label_en-US" xlink:label="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest in Unconsolidated Real Estate Joint Ventures, Number</link:label>
    <link:label id="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A_documentation_en-US" xlink:label="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of unconsolidated real estate joint ventures in which the entity holds interest.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber" xlink:label="loc_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A" xlink:to="lab_ofc_InterestInUnconsolidatedRealEstateJointVenturesNumber_E569830F87950D69FA86B4EB9E51947A" xlink:type="arc" />
    <link:label id="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_88056DE0B7DE70AEE993B4EB9E515878_negatedLabel_en-US" xlink:label="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_88056DE0B7DE70AEE993B4EB9E515878" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Investment Balance</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture" xlink:label="loc_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_88056DE0B7DE70AEE993B4EB9E515878" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_88056DE0B7DE70AEE993B4EB9E515878" xlink:to="lab_ofc_DistributionsReceivedInExcessOfInvestmentInUnconsolidatedRealEstateJointVenture_88056DE0B7DE70AEE993B4EB9E515878" xlink:type="arc" />
    <link:label id="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389_terseLabel_en-US" xlink:label="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of buildings operated by the joint venture</link:label>
    <link:label id="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389_label_en-US" xlink:label="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Buildings Operated by Joint Ventures Number</link:label>
    <link:label id="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389_documentation_en-US" xlink:label="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Number of buildings operated by the joint ventures.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_BuildingsOperatedByJointVenturesNumber" xlink:label="loc_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389" xlink:to="lab_ofc_BuildingsOperatedByJointVenturesNumber_616F085AC9C2A3E5B21EB4EB9E520389" xlink:type="arc" />
    <link:label id="lab_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214_terseLabel_en-US" xlink:label="lab_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Maximum exposure to loss</link:label>
    <link:label id="lab_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214_label_en-US" xlink:label="lab_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount" xlink:label="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214" xlink:to="lab_us-gaap_VariableInterestEntityEntityMaximumLossExposureAmount_F8EB355F728442E3A717B4EB9E529214" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_DAEA756FFC00AB913B5CB4EB9E520886_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_DAEA756FFC00AB913B5CB4EB9E520886" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Difference between carrying amount of investment and share or the equity in the joint venture</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_DAEA756FFC00AB913B5CB4EB9E520886_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity_DAEA756FFC00AB913B5CB4EB9E520886" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Difference Between Carrying Amount and Underlying Equity</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAbstract" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAbstract_7072CA2B6395FDDA4BE9B4EB9E528BBA" xlink:type="locator" />
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    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117_terseLabel_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Properties, net</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117_label_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Property, Net</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117_documentation_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The net book value of real estate property held for investment purposes reported by an equity method investment of the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet" xlink:label="loc_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyNet_EB60F586EACFE7DD60A3B4EB9E522117" xlink:type="locator" />
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    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationOtherAssets_1C56B9B6FBF6CC532810B4EB9E52E294_terseLabel_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationOtherAssets_1C56B9B6FBF6CC532810B4EB9E52E294" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other assets</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationOtherAssets_1C56B9B6FBF6CC532810B4EB9E52E294_label_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationOtherAssets_1C56B9B6FBF6CC532810B4EB9E52E294" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Other Assets</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationOtherAssets_1C56B9B6FBF6CC532810B4EB9E52E294_documentation_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationOtherAssets_1C56B9B6FBF6CC532810B4EB9E52E294" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the amount of other assets reported by an equity method investment of the entity.</link:label>
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    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA_totalLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total assets</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Assets</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA" xlink:to="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets_B5CD2A12AA256DC686B8B4EB9E5259FA" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Liabilities (primarily debt)</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2" xlink:to="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities_5DD965D75071FE186A32B4EB9E52B9F2" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Owners' equity</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment Summarized Financial Information, Equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68" xlink:to="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationEquity_411B087E9F05FFAC6539B4EB9E527B68" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3_totalLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total liabilities and owners' equity</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Liabilities and Equity</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3" xlink:to="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilitiesAndEquity_3EC35D86C501CF4E7970B4EB9E5270B3" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Condensed statements of operations for unconsolidated real estate joint venture</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Income Statement [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1" xlink:to="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationIncomeStatementAbstract_6A5893D13489C4E16AA6B4EB9E5217B1" xlink:type="arc" />
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B_terseLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Revenue</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue" xlink:label="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B" xlink:to="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationRevenue_86FCEA81F50C44ABF4DFB4EB9E52C35B" xlink:type="arc" />
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799_negatedLabel_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Property operating expenses</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799_label_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Property, Operating Expenses</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799_documentation_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of costs incurred that are directly related to generating revenues from leased and rented property or equipment reported by an equity method investment of the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses" xlink:label="loc_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799" xlink:to="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationPropertyOperatingExpenses_A9B7A432D19947CA6745B4EB9E52E799" xlink:type="arc" />
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0_negatedLabel_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Interest expense</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0_label_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Interest Expenses</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0_documentation_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of interest and debt related expenses associated with nonoperating financing activities reported by an equity method investment of the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses" xlink:label="loc_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0" xlink:to="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationInterestExpenses_7371162C231E3D566277B4EB9E5280E0" xlink:type="arc" />
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationDepreciationAndAmortizationExpenses_4AA494789A199DB55D6AB4EB9E522B0A_negatedLabel_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationDepreciationAndAmortizationExpenses_4AA494789A199DB55D6AB4EB9E522B0A" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization expense</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationDepreciationAndAmortizationExpenses_4AA494789A199DB55D6AB4EB9E522B0A_label_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationDepreciationAndAmortizationExpenses_4AA494789A199DB55D6AB4EB9E522B0A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Depreciation and Amortization Expenses</link:label>
    <link:label id="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationDepreciationAndAmortizationExpenses_4AA494789A199DB55D6AB4EB9E522B0A_documentation_en-US" xlink:label="lab_ofc_EquityMethodInvestmentSummarizedFinancialInformationDepreciationAndAmortizationExpenses_4AA494789A199DB55D6AB4EB9E522B0A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of depreciation and amortization expense reported by an equity method investment of the entity.</link:label>
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    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss_B1C7ABF7F0B64E145EA7B4EB9E521F63_totalLabel_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss_B1C7ABF7F0B64E145EA7B4EB9E521F63" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net loss</link:label>
    <link:label id="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss_B1C7ABF7F0B64E145EA7B4EB9E521F63_label_en-US" xlink:label="lab_us-gaap_EquityMethodInvestmentSummarizedFinancialInformationNetIncomeLoss_B1C7ABF7F0B64E145EA7B4EB9E521F63" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Equity Method Investment, Summarized Financial Information, Net Income (Loss)</link:label>
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    <link:label id="lab_ofc_ConsolidatedJointVenturesDisclosureAbstract_17374AA32FBAE28AC5DEB4EB9E52CFC2_label_en-US" xlink:label="lab_ofc_ConsolidatedJointVenturesDisclosureAbstract_17374AA32FBAE28AC5DEB4EB9E52CFC2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidated Joint Ventures Disclosure [Abstract]</link:label>
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    <link:label id="lab_ofc_ConsolidatedJointVenturesCarryingAmountAssets_8C55035A61FAD78CC8E6B4EB9E535FF2_terseLabel_en-US" xlink:label="lab_ofc_ConsolidatedJointVenturesCarryingAmountAssets_8C55035A61FAD78CC8E6B4EB9E535FF2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Assets</link:label>
    <link:label id="lab_ofc_ConsolidatedJointVenturesCarryingAmountAssets_8C55035A61FAD78CC8E6B4EB9E535FF2_label_en-US" xlink:label="lab_ofc_ConsolidatedJointVenturesCarryingAmountAssets_8C55035A61FAD78CC8E6B4EB9E535FF2" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Consolidated Joint Ventures, Carrying Amount Assets</link:label>
    <link:label id="lab_ofc_ConsolidatedJointVenturesCarryingAmountAssets_8C55035A61FAD78CC8E6B4EB9E535FF2_documentation_en-US" xlink:label="lab_ofc_ConsolidatedJointVenturesCarryingAmountAssets_8C55035A61FAD78CC8E6B4EB9E535FF2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The carrying amount of the consolidated joint venture's assets included in the reporting entity's statement of financial position.</link:label>
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    <link:label id="lab_us-gaap_PledgedAssetsNotSeparatelyReportedRealEstate_269F84F59A2E258213F2B4EB9E53ACF3_label_en-US" xlink:label="lab_us-gaap_PledgedAssetsNotSeparatelyReportedRealEstate_269F84F59A2E258213F2B4EB9E53ACF3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Pledged Assets, Not Separately Reported, Real Estate</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_PledgedAssetsNotSeparatelyReportedRealEstate" xlink:label="loc_us-gaap_PledgedAssetsNotSeparatelyReportedRealEstate_269F84F59A2E258213F2B4EB9E53ACF3" xlink:type="locator" />
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    <link:label id="lab_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_8AC5B3C89921D08D684FB4EB9E53F0F8_terseLabel_en-US" xlink:label="lab_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_8AC5B3C89921D08D684FB4EB9E53F0F8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Total Liabilities</link:label>
    <link:label id="lab_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_8AC5B3C89921D08D684FB4EB9E53F0F8_label_en-US" xlink:label="lab_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_8AC5B3C89921D08D684FB4EB9E53F0F8" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Variable Interest Entity, Consolidated, Carrying Amount, Liabilities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities" xlink:label="loc_us-gaap_VariableInterestEntityConsolidatedCarryingAmountLiabilities_8AC5B3C89921D08D684FB4EB9E53F0F8" xlink:type="locator" />
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    <link:label id="lab_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A_terseLabel_en-US" xlink:label="lab_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Limited Liability Company LLC or Limited Partnership LP Managing Member or General Partner Ownership Interest [Table]</link:label>
    <link:label id="lab_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A_label_en-US" xlink:label="lab_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Limited Liability Company LLC or Limited Partnership LP Managing Member or General Partner Ownership Interest [Table]</link:label>
    <link:label id="lab_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A_documentation_en-US" xlink:label="lab_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Disclosures related to the ownership of the LLC or LP by the managing member or general partner.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable" xlink:label="loc_ofc_ScheduleOfLimitedLiabilityCompanyLlcOrLimitedPartnershipLpManagingMemberOrGeneralPartnerOwnershipInterestTable_36058B87D89442B4C904C874B31D384A" xlink:type="locator" />
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    <link:label id="lab_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF_terseLabel_en-US" xlink:label="lab_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Corporate Office Properties, L.P.</link:label>
    <link:label id="lab_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF_label_en-US" xlink:label="lab_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Corporate Office Properties, L.P. [Member]</link:label>
    <link:label id="lab_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF_documentation_en-US" xlink:label="lab_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information pertaining to Corporate Office Properties, L.P.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_CorporateOfficePropertiesLPMember" xlink:label="loc_ofc_CorporateOfficePropertiesLPMember_5D3DF52843CDCF0AE545C874B31D0ADF" xlink:type="locator" />
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    <link:label id="lab_ofc_UnitsByNameAxis_A9FC9E5AC235B0F35E99C874B31D564B_terseLabel_en-US" xlink:label="lab_ofc_UnitsByNameAxis_A9FC9E5AC235B0F35E99C874B31D564B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Units by Name [Axis]</link:label>
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    <link:label id="lab_ofc_UnitsByNameAxis_A9FC9E5AC235B0F35E99C874B31D564B_documentation_en-US" xlink:label="lab_ofc_UnitsByNameAxis_A9FC9E5AC235B0F35E99C874B31D564B" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The axis of a table defines the relationship between the domain members or categories in the table and the line items or concepts that complete the table.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_UnitsByNameAxis" xlink:label="loc_ofc_UnitsByNameAxis_A9FC9E5AC235B0F35E99C874B31D564B" xlink:type="locator" />
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    <link:label id="lab_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573_terseLabel_en-US" xlink:label="lab_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Units, Class [Domain]</link:label>
    <link:label id="lab_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573_label_en-US" xlink:label="lab_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Units, Class [Domain]</link:label>
    <link:label id="lab_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573_documentation_en-US" xlink:label="lab_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Type or class of preferred units or special units.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_UnitsClassDomain" xlink:label="loc_ofc_UnitsClassDomain_A37355FB3C90B4D80FC9C874B31DF573" xlink:type="locator" />
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    <link:label id="lab_ofc_CommonUnitsMember_BEC23D6921E34C6C07B0C874B31D7585_terseLabel_en-US" xlink:label="lab_ofc_CommonUnitsMember_BEC23D6921E34C6C07B0C874B31D7585" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Common Units</link:label>
    <link:label id="lab_ofc_CommonUnitsMember_BEC23D6921E34C6C07B0C874B31D7585_label_en-US" xlink:label="lab_ofc_CommonUnitsMember_BEC23D6921E34C6C07B0C874B31D7585" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Common Units [Member]</link:label>
    <link:label id="lab_ofc_CommonUnitsMember_BEC23D6921E34C6C07B0C874B31D7585_documentation_en-US" xlink:label="lab_ofc_CommonUnitsMember_BEC23D6921E34C6C07B0C874B31D7585" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Common units representing ownership interest in the operating partnership.</link:label>
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    <link:label id="lab_ofc_SeriesGPreferredUnitsMember_CC7C6FB6FFC11A0C806BC874B31DF3E8_terseLabel_en-US" xlink:label="lab_ofc_SeriesGPreferredUnitsMember_CC7C6FB6FFC11A0C806BC874B31DF3E8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Series G Preferred Units</link:label>
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    <link:label id="lab_ofc_SeriesGPreferredUnitsMember_CC7C6FB6FFC11A0C806BC874B31DF3E8_documentation_en-US" xlink:label="lab_ofc_SeriesGPreferredUnitsMember_CC7C6FB6FFC11A0C806BC874B31DF3E8" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Series G preferred units representing ownership interest in the operating partnership.</link:label>
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    <link:label id="lab_ofc_SeriesHPreferredUnitsMember_571F3D75236BD99AC14DC874B31D02E2_terseLabel_en-US" xlink:label="lab_ofc_SeriesHPreferredUnitsMember_571F3D75236BD99AC14DC874B31D02E2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Series H Preferred Units</link:label>
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    <link:label id="lab_ofc_SeriesHPreferredUnitsMember_571F3D75236BD99AC14DC874B31D02E2_documentation_en-US" xlink:label="lab_ofc_SeriesHPreferredUnitsMember_571F3D75236BD99AC14DC874B31D02E2" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Series H preferred units representing ownership interest in the operating partnership.</link:label>
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    <link:label id="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_5AD3C6C5D1082C4999EDC49E5EE5F8F6_totalLabel_en-US" xlink:label="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_5AD3C6C5D1082C4999EDC49E5EE5F8F6" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Segement property operating expenses</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment" xlink:label="loc_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_5AD3C6C5D1082C4999EDC49E5EE5F8F6" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_5AD3C6C5D1082C4999EDC49E5EE5F8F6" xlink:to="lab_ofc_SegmentReportingDirectCostsOfLeasedAndRentedPropertyOrEquipment_5AD3C6C5D1082C4999EDC49E5EE5F8F6" xlink:type="arc" />
    <link:label id="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_AFC8F22FB85BCE654FF0C49E5EE6E6B8_negatedTerseLabel_en-US" xlink:label="lab_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_AFC8F22FB85BCE654FF0C49E5EE6E6B8" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Less: Property operating expenses from discontinued operations (Note 13)</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense" xlink:label="loc_ofc_DisposalGroupIncludingDiscontinuedOperationPropertyOperatingExpense_AFC8F22FB85BCE654FF0C49E5EE6E6B8" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_8FFA2E490831305A0EABC49E5EE6A110_verboseLabel_en-US" xlink:label="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_8FFA2E490831305A0EABC49E5EE6A110" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Total property operating expenses</link:label>
    <link:label id="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_8FFA2E490831305A0EABC49E5EE6A110_label_en-US" xlink:label="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_8FFA2E490831305A0EABC49E5EE6A110" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Direct Costs of Leased and Rented Property or Equipment</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_8FFA2E490831305A0EABC49E5EE6A110" xlink:to="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_8FFA2E490831305A0EABC49E5EE6A110" xlink:type="arc" />
    <link:label id="lab_us-gaap_OperatingIncomeLossAbstract_52CDFE5CA9774E4FC5ABC49E5EE6AE91_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingIncomeLossAbstract_52CDFE5CA9774E4FC5ABC49E5EE6AE91" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Computation of net operating income from service operations</link:label>
    <link:label id="lab_us-gaap_OperatingIncomeLossAbstract_52CDFE5CA9774E4FC5ABC49E5EE6AE91_label_en-US" xlink:label="lab_us-gaap_OperatingIncomeLossAbstract_52CDFE5CA9774E4FC5ABC49E5EE6AE91" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Income (Loss) [Abstract]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OperatingIncomeLossAbstract" xlink:label="loc_us-gaap_OperatingIncomeLossAbstract_52CDFE5CA9774E4FC5ABC49E5EE6AE91" xlink:type="locator" />
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    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB_negatedLabel_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Construction contract and other service expenses</link:label>
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB_label_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Construction Contract and Other Service Expenses</link:label>
    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB_documentation_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The aggregate costs related to construction and development services and the aggregate costs related to other service operations during the reporting period</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ConstructionContractAndOtherServiceExpenses" xlink:label="loc_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB" xlink:to="lab_ofc_ConstructionContractAndOtherServiceExpenses_04E0B109607AF5238CB8C49E5EE67DBB" xlink:type="arc" />
    <link:label id="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D_totalLabel_en-US" xlink:label="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">NOI from service operations</link:label>
    <link:label id="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D_label_en-US" xlink:label="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Net Operating Income (Loss) from Service Operations</link:label>
    <link:label id="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D_documentation_en-US" xlink:label="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the computation of NOI from service operations, which is the difference between Construction contract and other service revenues and Construction contract and other service expenses.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NetOperatingIncomeLossFromServiceOperations" xlink:label="loc_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D" xlink:to="lab_ofc_NetOperatingIncomeLossFromServiceOperations_6942BEA5E99A7317CD07C49E5EE62B9D" xlink:type="arc" />
    <link:label id="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361_terseLabel_en-US" xlink:label="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Reconciliation of NOI from real estate operations and NOI from service operations to (loss) income from continuing operations</link:label>
    <link:label id="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361_label_en-US" xlink:label="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Segment Reporting Reconciling Item for Operating Profit (Loss) from Segment to Consolidated [Abstract]</link:label>
    <link:label id="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361_documentation_en-US" xlink:label="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract" xlink:label="loc_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361" xlink:to="lab_ofc_SegmentReportingReconcilingItemForOperatingProfitLossFromSegmentToConsolidatedAbstract_D08ACA1DAC660337282BC49E5EE65361" xlink:type="arc" />
    <link:label id="lab_ofc_SegmentReportingOperatingIncome_B8FBB79FE45627ECA13BC49E5EE63195_terseLabel_en-US" xlink:label="lab_ofc_SegmentReportingOperatingIncome_B8FBB79FE45627ECA13BC49E5EE63195" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">NOI from real estate operations</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_SegmentReportingOperatingIncome" xlink:label="loc_ofc_SegmentReportingOperatingIncome_B8FBB79FE45627ECA13BC49E5EE63195" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_SegmentReportingOperatingIncome_B8FBB79FE45627ECA13BC49E5EE63195" xlink:to="lab_ofc_SegmentReportingOperatingIncome_B8FBB79FE45627ECA13BC49E5EE63195" xlink:type="arc" />
    <link:label id="lab_ofc_NetOperatingIncomeLossFromServiceOperations_9850E4CED3EE50B0CB09C49E5EE6ABB2_terseLabel_en-US" xlink:label="lab_ofc_NetOperatingIncomeLossFromServiceOperations_9850E4CED3EE50B0CB09C49E5EE6ABB2" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">NOI from service operations</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NetOperatingIncomeLossFromServiceOperations" xlink:label="loc_ofc_NetOperatingIncomeLossFromServiceOperations_9850E4CED3EE50B0CB09C49E5EE6ABB2" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NetOperatingIncomeLossFromServiceOperations_9850E4CED3EE50B0CB09C49E5EE6ABB2" xlink:to="lab_ofc_NetOperatingIncomeLossFromServiceOperations_9850E4CED3EE50B0CB09C49E5EE6ABB2" xlink:type="arc" />
    <link:label id="lab_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB_terseLabel_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest and other income</link:label>
    <link:label id="lab_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB_label_en-US" xlink:label="lab_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Nonoperating Income</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_OtherNonoperatingIncome" xlink:label="loc_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB" xlink:to="lab_us-gaap_OtherNonoperatingIncome_EAA4FCFAABFE06A8729BC49E5EE66AEB" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA_verboseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Equity in (loss) income of unconsolidated entities</link:label>
    <link:label id="lab_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Equity Method Investments</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromEquityMethodInvestments" xlink:label="loc_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA" xlink:to="lab_us-gaap_IncomeLossFromEquityMethodInvestments_8213F6004947CFB72177C49E5EE6CAAA" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeTaxExpenseBenefit_ECDF4DEEE3236D67C2C6C49E5EE69DA9_negatedLabel_en-US" xlink:label="lab_us-gaap_IncomeTaxExpenseBenefit_ECDF4DEEE3236D67C2C6C49E5EE69DA9" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Income tax (expense) benefit</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeTaxExpenseBenefit" xlink:label="loc_us-gaap_IncomeTaxExpenseBenefit_ECDF4DEEE3236D67C2C6C49E5EE69DA9" xlink:type="locator" />
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    <link:label id="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB_terseLabel_en-US" xlink:label="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Other adjustments:</link:label>
    <link:label id="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB_label_en-US" xlink:label="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Other Adjustments [Abstract]</link:label>
    <link:label id="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB_documentation_en-US" xlink:label="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US" />
    <link:loc xlink:href="ofc-20120630.xsd#ofc_OtherAdjustmentsAbstract" xlink:label="loc_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB" xlink:to="lab_ofc_OtherAdjustmentsAbstract_7FAEE43C3692ABF2CDE3C49E5EE68AAB" xlink:type="arc" />
    <link:label id="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F_negatedLabel_en-US" xlink:label="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F" xlink:role="http://www.xbrl.org/2009/role/negatedLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization associated with real estate operations</link:label>
    <link:label id="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F_label_en-US" xlink:label="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Depreciation and Amortization for Real Estate Operations</link:label>
    <link:label id="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F_documentation_en-US" xlink:label="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The current period expense charged against earnings on long-lived, physical real estate operations assets, and which are not intended for resale, to allocate or recognize the cost of such assets over their useful lives; or to record the reduction in book value of an intangible asset or deferred costs associated with real estate operations over the benefit period of such asset or costs; or to reflect consumption during the period of an asset that is not used in production.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DepreciationAndAmortizationForRealEstateOperations" xlink:label="loc_ofc_DepreciationAndAmortizationForRealEstateOperations_74A3F8C0D68F997BA944C49E5EE6BE3F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetImpairmentCharges_6A440B3FFC7C3E287C32C49E5EE6ADE0_negatedTerseLabel_en-US" xlink:label="lab_us-gaap_AssetImpairmentCharges_6A440B3FFC7C3E287C32C49E5EE6ADE0" xlink:role="http://www.xbrl.org/2009/role/negatedTerseLabel" xlink:type="resource" xml:lang="en-US">Impairment (losses) recoveries</link:label>
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    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1E1DA607ED36A1CF65B82E5448732119_terseLabel_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1E1DA607ED36A1CF65B82E5448732119" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Antidilutive securities excluded from computation of diluted earnings per share (in shares)</link:label>
    <link:label id="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1E1DA607ED36A1CF65B82E5448732119_label_en-US" xlink:label="lab_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1E1DA607ED36A1CF65B82E5448732119" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount" xlink:label="loc_us-gaap_AntidilutiveSecuritiesExcludedFromComputationOfEarningsPerShareAmount_1E1DA607ED36A1CF65B82E5448732119" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_37B336BC607C7F1D6431E6096A9F2B6F_terseLabel_en-US" xlink:label="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_37B336BC607C7F1D6431E6096A9F2B6F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discontinued Operations and Assets Held for Sale</link:label>
    <link:label id="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_37B336BC607C7F1D6431E6096A9F2B6F_label_en-US" xlink:label="lab_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_37B336BC607C7F1D6431E6096A9F2B6F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Disposal Groups, Including Discontinued Operations, Disclosure [Text Block]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock" xlink:label="loc_us-gaap_DisposalGroupsIncludingDiscontinuedOperationsDisclosureTextBlock_37B336BC607C7F1D6431E6096A9F2B6F" xlink:type="locator" />
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    <link:label id="lab_us-gaap_ScheduleOfRealEstatePropertiesTable_054735A0CC5847EBC11C395F08923C4D_terseLabel_en-US" xlink:label="lab_us-gaap_ScheduleOfRealEstatePropertiesTable_054735A0CC5847EBC11C395F08923C4D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Schedule of Real Estate Properties [Table]</link:label>
    <link:label id="lab_us-gaap_ScheduleOfRealEstatePropertiesTable_054735A0CC5847EBC11C395F08923C4D_label_en-US" xlink:label="lab_us-gaap_ScheduleOfRealEstatePropertiesTable_054735A0CC5847EBC11C395F08923C4D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Schedule of Real Estate Properties [Table]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_ScheduleOfRealEstatePropertiesTable" xlink:label="loc_us-gaap_ScheduleOfRealEstatePropertiesTable_054735A0CC5847EBC11C395F08923C4D" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RealEstatePropertiesAxis_3939F147EA58EB3C9C07395F0892714A_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesAxis_3939F147EA58EB3C9C07395F0892714A" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Axis]</link:label>
    <link:label id="lab_us-gaap_RealEstatePropertiesAxis_3939F147EA58EB3C9C07395F0892714A_label_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesAxis_3939F147EA58EB3C9C07395F0892714A" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Axis]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstatePropertiesAxis" xlink:label="loc_us-gaap_RealEstatePropertiesAxis_3939F147EA58EB3C9C07395F0892714A" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81_terseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Domain]</link:label>
    <link:label id="lab_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81_label_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Properties [Domain]</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstatePropertiesDomain" xlink:label="loc_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81" xlink:to="lab_us-gaap_RealEstatePropertiesDomain_A0C23C34E7F09CC4685E395F08927E81" xlink:type="arc" />
    <link:label id="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9_terseLabel_en-US" xlink:label="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Properties under construction</link:label>
    <link:label id="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9_label_en-US" xlink:label="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Properties under Construction [Member]</link:label>
    <link:label id="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9_documentation_en-US" xlink:label="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents real estate office properties under construction.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PropertiesUnderConstructionMember" xlink:label="loc_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9" xlink:to="lab_ofc_PropertiesUnderConstructionMember_B4357299A1CDD033502B395F08925AE9" xlink:type="arc" />
    <link:label id="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7_terseLabel_en-US" xlink:label="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Properties under redevelopment</link:label>
    <link:label id="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7_label_en-US" xlink:label="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Properties under Re Development [Member]</link:label>
    <link:label id="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7_documentation_en-US" xlink:label="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents real estate office properties under redevelopment.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_PropertiesUnderReDevelopmentMember" xlink:label="loc_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7" xlink:to="lab_ofc_PropertiesUnderReDevelopmentMember_88CE81043CC72AAA196C395F0892A4C7" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Property Location [Axis]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC_label_en-US" xlink:label="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Property Location [Axis]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents information regarding location of real estate properties.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertyLocationAxis" xlink:label="loc_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC" xlink:to="lab_ofc_RealEstatePropertyLocationAxis_FA872ABE1A073468727B395F08933EEC" xlink:type="arc" />
    <link:label id="lab_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891_terseLabel_en-US" xlink:label="lab_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Real Estate Property Location [Domain]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891_label_en-US" xlink:label="lab_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Real Estate Property Location [Domain]</link:label>
    <link:label id="lab_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891_documentation_en-US" xlink:label="lab_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents location of real estate properties.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RealEstatePropertyLocationDomain" xlink:label="loc_ofc_RealEstatePropertyLocationDomain_36BA3C67F0A4E60554E0395F08930891" xlink:type="locator" />
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    <link:label id="lab_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA_terseLabel_en-US" xlink:label="lab_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Huntsville</link:label>
    <link:label id="lab_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA_label_en-US" xlink:label="lab_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Huntsville [Member]</link:label>
    <link:label id="lab_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA_documentation_en-US" xlink:label="lab_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the Huntsville location where construction development or redevelopment activities are conducted by the entity.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_HuntsvilleMember" xlink:label="loc_ofc_HuntsvilleMember_1FB711B85F45CF213771395F08932ECA" xlink:type="locator" />
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    <link:label id="lab_us-gaap_RealEstatePropertiesLineItems_235CC63528D8B984D584395F0893A084_verboseLabel_en-US" xlink:label="lab_us-gaap_RealEstatePropertiesLineItems_235CC63528D8B984D584395F0893A084" xlink:role="http://www.xbrl.org/2003/role/verboseLabel" xlink:type="resource" xml:lang="en-US">Construction and Redevelopment Activities</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_RealEstatePropertiesLineItems" xlink:label="loc_us-gaap_RealEstatePropertiesLineItems_235CC63528D8B984D584395F0893A084" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_RealEstatePropertiesLineItems_235CC63528D8B984D584395F0893A084" xlink:to="lab_us-gaap_RealEstatePropertiesLineItems_235CC63528D8B984D584395F0893A084" xlink:type="arc" />
    <link:label id="lab_ofc_SquareFeetPlacedInServiceOnPropertiesAsOfPriorYearEnd_2433B2DB0622D379CD4B395F0894510F_terseLabel_en-US" xlink:label="lab_ofc_SquareFeetPlacedInServiceOnPropertiesAsOfPriorYearEnd_2433B2DB0622D379CD4B395F0894510F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Square feet placed in service on properties as of prior year end (in square feet)</link:label>
    <link:label id="lab_ofc_SquareFeetPlacedInServiceOnPropertiesAsOfPriorYearEnd_2433B2DB0622D379CD4B395F0894510F_label_en-US" xlink:label="lab_ofc_SquareFeetPlacedInServiceOnPropertiesAsOfPriorYearEnd_2433B2DB0622D379CD4B395F0894510F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Square Feet Placed in Service on Properties as of Prior Year End</link:label>
    <link:label id="lab_ofc_SquareFeetPlacedInServiceOnPropertiesAsOfPriorYearEnd_2433B2DB0622D379CD4B395F0894510F_documentation_en-US" xlink:label="lab_ofc_SquareFeetPlacedInServiceOnPropertiesAsOfPriorYearEnd_2433B2DB0622D379CD4B395F0894510F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of square footage placed into service as of the prior year end on properties becoming fully operational during the current period.</link:label>
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    <link:label id="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3_terseLabel_en-US" xlink:label="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Number of real estate properties placed into service</link:label>
    <link:label id="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3_label_en-US" xlink:label="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Number of Real Estate Properties Placed In Service</link:label>
    <link:label id="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3_documentation_en-US" xlink:label="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents the number of real estate properties placed in service during the year.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_NumberOfRealEstatePropertiesPlacedInService" xlink:label="loc_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3" xlink:to="lab_ofc_NumberOfRealEstatePropertiesPlacedInService_EBA853D554DE210D65C3395F0894F3A3" xlink:type="arc" />
    <link:label id="lab_ofc_SquareFeetOfPropertiesPlacedInService_72008D413C7840969FF3395F08941EBE_terseLabel_en-US" xlink:label="lab_ofc_SquareFeetOfPropertiesPlacedInService_72008D413C7840969FF3395F08941EBE" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Square feet placed in service on properties during the period (in square feet)</link:label>
    <link:label id="lab_ofc_SquareFeetOfPropertiesPlacedInService_72008D413C7840969FF3395F08941EBE_label_en-US" xlink:label="lab_ofc_SquareFeetOfPropertiesPlacedInService_72008D413C7840969FF3395F08941EBE" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Square Feet of Properties Placed in Service</link:label>
    <link:label id="lab_ofc_SquareFeetOfPropertiesPlacedInService_72008D413C7840969FF3395F08941EBE_documentation_en-US" xlink:label="lab_ofc_SquareFeetOfPropertiesPlacedInService_72008D413C7840969FF3395F08941EBE" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The amount of square footage placed into service during the period.</link:label>
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    <link:label id="lab_ofc_PrepaidExpensesAndOtherAssetsTextBlock_2ADA82F7C3547921DA05E60006CA5A60_label_en-US" xlink:label="lab_ofc_PrepaidExpensesAndOtherAssetsTextBlock_2ADA82F7C3547921DA05E60006CA5A60" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Prepaid Expenses and Other Assets [Text Block]</link:label>
    <link:label id="lab_ofc_PrepaidExpensesAndOtherAssetsTextBlock_2ADA82F7C3547921DA05E60006CA5A60_documentation_en-US" xlink:label="lab_ofc_PrepaidExpensesAndOtherAssetsTextBlock_2ADA82F7C3547921DA05E60006CA5A60" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">This block of text may be used to disclose part or all of the information related to prepaid expenses and other assets.</link:label>
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    <link:label id="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_9A41B8DDAE9DE3B40FD4BB2505BA9AEC_terseLabel_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_9A41B8DDAE9DE3B40FD4BB2505BA9AEC" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest Rate Derivatives</link:label>
    <link:label id="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_9A41B8DDAE9DE3B40FD4BB2505BA9AEC_label_en-US" xlink:label="lab_us-gaap_DerivativeInstrumentsAndHedgingActivitiesDisclosureTextBlock_9A41B8DDAE9DE3B40FD4BB2505BA9AEC" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Derivative Instruments and Hedging Activities Disclosure [Text Block]</link:label>
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    <link:label id="lab_ofc_ScheduleOfOperatingPartnershipOwnershipTableTextBlock_7935C11BB3BC9D0F9A7938F10614FA20_terseLabel_en-US" xlink:label="lab_ofc_ScheduleOfOperatingPartnershipOwnershipTableTextBlock_7935C11BB3BC9D0F9A7938F10614FA20" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Summary of forms of ownership and percentage of ownership forms</link:label>
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    <link:label id="lab_us-gaap_IncomeStatementAbstract_84899D116C1A7E6ADB6DBF2A2DAA8BA7_label_en-US" xlink:label="lab_us-gaap_IncomeStatementAbstract_84899D116C1A7E6ADB6DBF2A2DAA8BA7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income Statement [Abstract]</link:label>
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    <link:label id="lab_us-gaap_RevenuesAbstract_4C8E0BC5E0CFA8E68E2DBF2A2DABE03F_terseLabel_en-US" xlink:label="lab_us-gaap_RevenuesAbstract_4C8E0BC5E0CFA8E68E2DBF2A2DABE03F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Revenues</link:label>
    <link:label id="lab_us-gaap_RevenuesAbstract_4C8E0BC5E0CFA8E68E2DBF2A2DABE03F_label_en-US" xlink:label="lab_us-gaap_RevenuesAbstract_4C8E0BC5E0CFA8E68E2DBF2A2DABE03F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Revenues [Abstract]</link:label>
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    <link:label id="lab_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96_terseLabel_en-US" xlink:label="lab_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Rental revenue</link:label>
    <link:label id="lab_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96_label_en-US" xlink:label="lab_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Rental Revenue</link:label>
    <link:label id="lab_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96_documentation_en-US" xlink:label="lab_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">The minimum amount of rents earned during the period from lessees based on the terms of contractual arrangements. Includes amounts recognized in the current period related to favorable or unfavorable in-place lease intangibles on acquired leases that are amortized as a reduction of or addition to rental revenue, revenue from early lease terminations and percentage rent revenue.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_RentalRevenue" xlink:label="loc_ofc_RentalRevenue_2CCE32C2DE12CC548B30BF2A2DABCA96" xlink:type="locator" />
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    <link:label id="lab_ofc_TenantReimbursementsAndOtherRealEstateOperationsRevenue_42D909A41FBA821F086BBF2A2DABEEAB_terseLabel_en-US" xlink:label="lab_ofc_TenantReimbursementsAndOtherRealEstateOperationsRevenue_42D909A41FBA821F086BBF2A2DABEEAB" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Tenant recoveries and other real estate operations revenue</link:label>
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    <link:label id="lab_ofc_TenantReimbursementsAndOtherRealEstateOperationsRevenue_42D909A41FBA821F086BBF2A2DABEEAB_documentation_en-US" xlink:label="lab_ofc_TenantReimbursementsAndOtherRealEstateOperationsRevenue_42D909A41FBA821F086BBF2A2DABEEAB" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Allowable charges due a landlord from its tenant in accordance with the provisions of their lease agreement. In retail store and office building leases, for example, tenant reimbursements may cover items such as taxes, utilities, and common area expenses. This element also includes other real estate operations revenue.</link:label>
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    <link:label id="lab_us-gaap_OperatingCostsAndExpensesAbstract_82FFD2433FA7C0DFEC04BF2A2DAB845C_terseLabel_en-US" xlink:label="lab_us-gaap_OperatingCostsAndExpensesAbstract_82FFD2433FA7C0DFEC04BF2A2DAB845C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Expenses</link:label>
    <link:label id="lab_us-gaap_OperatingCostsAndExpensesAbstract_82FFD2433FA7C0DFEC04BF2A2DAB845C_label_en-US" xlink:label="lab_us-gaap_OperatingCostsAndExpensesAbstract_82FFD2433FA7C0DFEC04BF2A2DAB845C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Operating Costs and Expenses [Abstract]</link:label>
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    <link:label id="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_827BB70AB6D99566ED36BF2A2DAB821F_terseLabel_en-US" xlink:label="lab_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_827BB70AB6D99566ED36BF2A2DAB821F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Property operating expenses</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment" xlink:label="loc_us-gaap_DirectCostsOfLeasedAndRentedPropertyOrEquipment_827BB70AB6D99566ED36BF2A2DAB821F" xlink:type="locator" />
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    <link:label id="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_FC58C6155BE7143042E7BF2A2DACCD41_terseLabel_en-US" xlink:label="lab_ofc_DepreciationAndAmortizationForRealEstateOperations_FC58C6155BE7143042E7BF2A2DACCD41" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Depreciation and amortization associated with real estate operations</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_DepreciationAndAmortizationForRealEstateOperations" xlink:label="loc_ofc_DepreciationAndAmortizationForRealEstateOperations_FC58C6155BE7143042E7BF2A2DACCD41" xlink:type="locator" />
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    <link:label id="lab_ofc_ConstructionContractAndOtherServiceExpenses_326B97963F4BB4C9A7CDBF2A2DACB073_terseLabel_en-US" xlink:label="lab_ofc_ConstructionContractAndOtherServiceExpenses_326B97963F4BB4C9A7CDBF2A2DACB073" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Construction contract and other service expenses</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_ConstructionContractAndOtherServiceExpenses" xlink:label="loc_ofc_ConstructionContractAndOtherServiceExpenses_326B97963F4BB4C9A7CDBF2A2DACB073" xlink:type="locator" />
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    <link:label id="lab_us-gaap_AssetImpairmentCharges_348680D23CA0862C8EE7BF2A2DAC5A13_terseLabel_en-US" xlink:label="lab_us-gaap_AssetImpairmentCharges_348680D23CA0862C8EE7BF2A2DAC5A13" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Impairment losses (recoveries)</link:label>
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    <link:label id="lab_us-gaap_GeneralAndAdministrativeExpense_72193E416B06ADAC2EDABF2A2DACCB6D_terseLabel_en-US" xlink:label="lab_us-gaap_GeneralAndAdministrativeExpense_72193E416B06ADAC2EDABF2A2DACCB6D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">General and administrative expenses</link:label>
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    <link:label id="lab_ofc_BusinessDevelopmentExpensesAndLandCarryCosts_E261341FBC8C7423F348BF2A2DACDD0E_terseLabel_en-US" xlink:label="lab_ofc_BusinessDevelopmentExpensesAndLandCarryCosts_E261341FBC8C7423F348BF2A2DACDD0E" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Business development expenses and land carry costs</link:label>
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    <link:label id="lab_us-gaap_CostsAndExpenses_D430EEBE2A66F0757AB2BF2A2DAC257E_totalLabel_en-US" xlink:label="lab_us-gaap_CostsAndExpenses_D430EEBE2A66F0757AB2BF2A2DAC257E" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Total operating expenses</link:label>
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_CostsAndExpenses" xlink:label="loc_us-gaap_CostsAndExpenses_D430EEBE2A66F0757AB2BF2A2DAC257E" xlink:type="locator" />
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    <link:label id="lab_us-gaap_IncomeLossFromContinuingOperations_4F578B12270F1FC26F57BF2A2DAEF514_label_en-US" xlink:label="lab_us-gaap_IncomeLossFromContinuingOperations_4F578B12270F1FC26F57BF2A2DAEF514" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Income (Loss) from Continuing Operations Attributable to Parent</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperations_4F578B12270F1FC26F57BF2A2DAEF514" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperations_4F578B12270F1FC26F57BF2A2DAEF514" xlink:type="arc" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxAttributableToReportingEntity_B3FEE0B8F6BD0572CCD5BF2A2DAEACF9" xlink:type="locator" />
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    <link:label id="lab_us-gaap_EarningsPerShareBasicAbstract_37030056697CA74EE6A7BF2A2DAED3B7_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasicAbstract_37030056697CA74EE6A7BF2A2DAED3B7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Basic earnings per common share</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareBasicAbstract" xlink:label="loc_us-gaap_EarningsPerShareBasicAbstract_37030056697CA74EE6A7BF2A2DAED3B7" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_4A27D19829C7DD7EBBACBF2A2DAEEF08" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_4A27D19829C7DD7EBBACBF2A2DAEEF08" xlink:to="lab_us-gaap_IncomeLossFromContinuingOperationsPerBasicShare_4A27D19829C7DD7EBBACBF2A2DAEEF08" xlink:type="arc" />
    <link:label id="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_E97550D3848C6691AF4FBF2A2DAE55B8_terseLabel_en-US" xlink:label="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_E97550D3848C6691AF4FBF2A2DAE55B8" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Discontinued operations</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_E97550D3848C6691AF4FBF2A2DAE55B8" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_E97550D3848C6691AF4FBF2A2DAE55B8" xlink:to="lab_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerBasicShare_E97550D3848C6691AF4FBF2A2DAE55B8" xlink:type="arc" />
    <link:label id="lab_us-gaap_EarningsPerShareBasic_C991A5D26C9223E3B739BF2A2DAE7CDB_totalLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareBasic_C991A5D26C9223E3B739BF2A2DAE7CDB" xlink:role="http://www.xbrl.org/2003/role/totalLabel" xlink:type="resource" xml:lang="en-US">Net income (loss) attributable to COPT common shareholders (in dollars per share)</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareBasic" xlink:label="loc_us-gaap_EarningsPerShareBasic_C991A5D26C9223E3B739BF2A2DAE7CDB" xlink:type="locator" />
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    <link:label id="lab_us-gaap_EarningsPerShareDilutedAbstract_DFB84BEE659B086C9648BF2A2DAF450B_terseLabel_en-US" xlink:label="lab_us-gaap_EarningsPerShareDilutedAbstract_DFB84BEE659B086C9648BF2A2DAF450B" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Diluted earnings per common share</link:label>
    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareDilutedAbstract" xlink:label="loc_us-gaap_EarningsPerShareDilutedAbstract_DFB84BEE659B086C9648BF2A2DAF450B" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromContinuingOperationsPerDilutedShare_63EC42F1918769BD80D0BF2A2DAF9046" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare" xlink:label="loc_us-gaap_IncomeLossFromDiscontinuedOperationsNetOfTaxPerDilutedShare_2E6A4B5FA01427EE6D0BBF2A2DAF5941" xlink:type="locator" />
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    <link:loc xlink:href="http://xbrl.fasb.org/us-gaap/2011/elts/us-gaap-2011-01-31.xsd#us-gaap_EarningsPerShareDiluted" xlink:label="loc_us-gaap_EarningsPerShareDiluted_3A80FDAA576C2C422B18BF2A2DAF12EE" xlink:type="locator" />
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    <link:label id="lab_us-gaap_DesignatedAsHedgingInstrumentMember_D3BC8CEEE61DAE8A0B78C5EC0C0906E1_terseLabel_en-US" xlink:label="lab_us-gaap_DesignatedAsHedgingInstrumentMember_D3BC8CEEE61DAE8A0B78C5EC0C0906E1" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Designated</link:label>
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    <link:label id="lab_ofc_DedesignatedHedgeMember_603467BEDBF333D4F3BAC5EC0C09643F_terseLabel_en-US" xlink:label="lab_ofc_DedesignatedHedgeMember_603467BEDBF333D4F3BAC5EC0C09643F" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Not-designated</link:label>
    <link:label id="lab_ofc_DedesignatedHedgeMember_603467BEDBF333D4F3BAC5EC0C09643F_label_en-US" xlink:label="lab_ofc_DedesignatedHedgeMember_603467BEDBF333D4F3BAC5EC0C09643F" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Dedesignated Hedge [Member]</link:label>
    <link:label id="lab_ofc_DedesignatedHedgeMember_603467BEDBF333D4F3BAC5EC0C09643F_documentation_en-US" xlink:label="lab_ofc_DedesignatedHedgeMember_603467BEDBF333D4F3BAC5EC0C09643F" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Derivative instruments which have been de-designated as hedging instruments.</link:label>
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    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012Member_FA9D02C08D8296E6690CC5EC0C0AE3C9_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012Member_FA9D02C08D8296E6690CC5EC0C0AE3C9" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date January 3, 2012</link:label>
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    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012Member_FA9D02C08D8296E6690CC5EC0C0AE3C9_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012Member_FA9D02C08D8296E6690CC5EC0C0AE3C9" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents a interest rate swap derivative effective on January 3, 2012.</link:label>
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    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012OneMember_32375A998B7137556EEFC5EC0C0A4527_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012OneMember_32375A998B7137556EEFC5EC0C0A4527" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap one, effective date January 3, 2012</link:label>
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    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary32012OneMember_32375A998B7137556EEFC5EC0C0A4527" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary32012OneMember_32375A998B7137556EEFC5EC0C0A4527" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap two, effective date January 3, 2012</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap, Effective Date January 3, 2012 Two [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents a two interest rate swap derivative effective on January 3, 2012.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember" xlink:label="loc_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary32012TwoMember_44E76F2147A04CEE1C03C5EC0C0A086D" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap three, effective date January 3, 2012</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap, Effective Date January 3, 2012 Three [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents a three interest rate swap derivative effective on January 3, 2012.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember" xlink:label="loc_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary32012ThreeMember_4DD477BF657119A28675C5EC0C0A51B7" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date November 2, 2010</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Effective Date November 2, 2010 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative effective on November 2, 2010.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateNovember22010Member" xlink:label="loc_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0" xlink:to="lab_ofc_InterestRateSwapEffectiveDateNovember22010Member_786E21C21673E9A4CAF1C5EC0C0A76E0" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date January 3, 2011</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Effective Date January 3, 2011 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative effective on January 3, 2011.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateJanuary32011Member" xlink:label="loc_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary32011Member_7B30A9C66F6A3559BCDDC5EC0C0A3B84" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, two, effective date January 3, 2011</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Effective Date January 4, 2011 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative effective on January 4, 2011.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateJanuary42011Member" xlink:label="loc_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary42011Member_073FF77319E4DDA5332BC5EC0C0ABC6C" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date January 2, 2009</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Effective Date January 2, 2009 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative effective on January 2, 2009.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateJanuary22009Member" xlink:label="loc_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary22009Member_0FB9E5A429BF455078A6C5EC0C0A70A7" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date January 1, 2010</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544_label_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap Effective Date January 1, 2010 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative effective on January 1, 2010.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapEffectiveDateJanuary12010Member" xlink:label="loc_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544" xlink:to="lab_ofc_InterestRateSwapEffectiveDateJanuary12010Member_B131F2D790B37AEA53EDC5EC0C0AE544" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524_terseLabel_en-US" xlink:label="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date September 30, 2011</link:label>
    <link:label id="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524_label_en-US" xlink:label="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Notional Amount 100000 Effective Date September 30, 2011 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524_documentation_en-US" xlink:label="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative with a notional amount of $100,000,000 effective September 30, 2011.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member" xlink:label="loc_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524" xlink:to="lab_ofc_InterestRateNotionalAmount100000EffectiveDateSeptember302011Member_40A98060A0981DF06EB4C5EC0C0A0524" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145_terseLabel_en-US" xlink:label="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap two, effective date September 30, 2011</link:label>
    <link:label id="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145_label_en-US" xlink:label="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Notional Amount 75000 Effective Date September 30, 2011 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145_documentation_en-US" xlink:label="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative with a notional amount of $75,000,000 effective September 30, 2011.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member" xlink:label="loc_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145" xlink:to="lab_ofc_InterestRateNotionalAmount75000EffectiveDateSeptember302011Member_57AE856AF73CD4696D08C5EC0C0A2145" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap, effective date December 30, 2011</link:label>
    <link:label id="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D_label_en-US" xlink:label="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap, Notional Amount 100000 Effective Date December 30 2011 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative with a notional amount of $100,000,000 effective December 30, 2011.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member" xlink:label="loc_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D" xlink:to="lab_ofc_InterestRateSwapNotionalAmount100000EffectiveDateDecember302011Member_A20B8E63C8F55392C418C5EC0C0AC83D" xlink:type="arc" />
    <link:label id="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034_terseLabel_en-US" xlink:label="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034" xlink:role="http://www.xbrl.org/2003/role/terseLabel" xlink:type="resource" xml:lang="en-US">Interest rate swap two, effective date December 30, 2011</link:label>
    <link:label id="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034_label_en-US" xlink:label="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034" xlink:role="http://www.xbrl.org/2003/role/label" xlink:type="resource" xml:lang="en-US">Interest Rate Swap, Notional Amount 75000 Effective Date December 30 2011 [Member]</link:label>
    <link:label id="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034_documentation_en-US" xlink:label="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034" xlink:role="http://www.xbrl.org/2003/role/documentation" xlink:type="resource" xml:lang="en-US">Represents an interest rate swap derivative with a notional amount of $75,000,000 effective December 30, 2011.</link:label>
    <link:loc xlink:href="ofc-20120630.xsd#ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member" xlink:label="loc_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034" xlink:type="locator" />
    <link:labelArc order="1" xlink:arcrole="http://www.xbrl.org/2003/arcrole/concept-label" xlink:from="loc_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034" xlink:to="lab_ofc_InterestRateSwapNotionalAmount75000EffectiveDateDecember302011Member_387A02E73BACF017A014C5EC0C0A8034" xlink:type="arc" />
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