<SUBMISSION>
<ACCESSION-NUMBER>0001217093-05-000122
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20050930
<FILING-DATE>20051004
<DATE-OF-FILING-DATE-CHANGE>20051004
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>BOSTON PROPERTIES INC
<CIK>0001037540
<ASSIGNED-SIC>6798
<IRS-NUMBER>042473675
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>111 HUNTINGTON AVEUE
<STREET2>SUITE 300
<CITY>BOSTON
<STATE>MA
<ZIP>02199
<PHONE>6172363300
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>111 HUNTINGTON AVEUE
<STREET2>SUITE 300
<CITY>BOSTON
<STATE>MA
<ZIP>02199
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>PATRICOF ALAN J
<CIK>0001217107
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-13087
<FILM-NUMBER>051119516
</FILING-VALUES>
<MAIL-ADDRESS>
<STREET1>C/O BOSTON PROPERTIES KELLI A DILUGLIO
<CITY>BOSTON
<STATE>MA
<ZIP>02199
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-09-30</periodOfReport>

    <issuer>
        <issuerCik>0001037540</issuerCik>
        <issuerName>BOSTON PROPERTIES INC</issuerName>
        <issuerTradingSymbol>BXP</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001217107</rptOwnerCik>
            <rptOwnerName>PATRICOF ALAN J</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>APAX PARTNERS, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>445 PARK AVENUE</rptOwnerStreet2>
            <rptOwnerCity>NEW YORK</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2005-09-30</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>232.72</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F2"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>232.72</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>12025.03</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The Phantom Stock Units convert to Common Stock on a 1-for-1 basis.</footnote>
        <footnote id="F2">The Phantom Stock Units are awarded under the Boston Properties, Inc. 1997 Stock Option and Incentive Plan to non-employee directors who elected to receive Phantom Stock Units in lieu of director compensation fees.  The Phantom Stock Units are to be settled in shares of Common Stock upon the Reporting Person's retirement from the Boston Properties Board of Directors.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Kelli A. DiLuglio, as Attorney-in-Fact</signatureName>
        <signatureDate>2005-10-04</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
