<SUBMISSION>
<ACCESSION-NUMBER>0001214276-04-000001
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20040105
<FILING-DATE>20040107
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>KINSELLA DALE F
<CIK>0001214276
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-12675
<FILM-NUMBER>04513136
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>12200 W OLYMPIC BLVD
<STREET2>SUITE 200
<CITY>LOS ANGELES
<STATE>CA
<ZIP>90064
</MAIL-ADDRESS>
</REPORTING-OWNER>
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>KILROY REALTY CORP
<CIK>0001025996
<ASSIGNED-SIC>6798
<IRS-NUMBER>954598246
<STATE-OF-INCORPORATION>MD
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>2250 E IMPERIAL HWY
<STREET2>C/O KILROY INDUSTRIES
<CITY>EL SEGUNDO
<STATE>CA
<ZIP>90245
<PHONE>3105635500
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>C/O KILROY INDUSTRIES
<STREET2>2250 E IMPERIAL HIGHWAY #1200
<CITY>EL SEGUNDO
<STATE>CA
<ZIP>90245
</MAIL-ADDRESS>
</ISSUER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
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    <documentType>4</documentType><periodOfReport>2004-01-05</periodOfReport>
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        <issuerName>KILROY REALTY CORP</issuerName>
        <issuerTradingSymbol>KRC</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001214276</rptOwnerCik>
            <rptOwnerName>KINSELLA DALE F</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>12200 WEST OLYMPIC BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 200</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90064</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
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Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Common Stock Option (right to buy)</value></securityTitle><conversionOrExercisePrice><value>25.77</value></conversionOrExercisePrice><exerciseDate><value>2005-02-19</value><footnoteId id="F6"/></exerciseDate><expirationDate><value>2012-02-19</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5000</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">The initial option grant vested in three equal installments on January 31, 1998, 1999, and 2000.</footnote><footnote id="F2">The initial option grant vested in three equal installments on February 2, 1999, 2000, and 2001.</footnote><footnote id="F3">The initial option grant vested in three equal installments on February 18, 2000, 2001, and 2002.</footnote><footnote id="F4">The initial option grant vested in three equal installments on February 18, 2001, 2002, and 2003.</footnote><footnote id="F5">The initial option grant vests in three equal installments on February 18, 2002, 2003, and 2004.</footnote><footnote id="F6">The initial option grant vests in three equal installments on February 19, 2003, 2004, and 2005.</footnote></footnotes><remarks/><ownerSignature><signatureName>Dale F. Kinsella</signatureName><signatureDate>2004-01-07</signatureDate></ownerSignature></ownershipDocument>

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</SUBMISSION>
