<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType><periodOfReport>2003-08-07</periodOfReport>
    <issuer>
        <issuerCik>0000783280</issuerCik>
        <issuerName>DUKE REALTY CORP</issuerName>
        <issuerTradingSymbol>DRE</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001024239</rptOwnerCik>
            <rptOwnerName>HEFNER THOMAS L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>600 E. 96TH STREET, SUITE 100</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>INDIANAPOLIS</rptOwnerCity>
            <rptOwnerState>IN</rptOwnerState>
            <rptOwnerZipCode>46240</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Chairman of the Board &amp; CEO</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>356305</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Trust</value><footnoteId id="F1"/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>205051</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Spouse's Trust</value><footnoteId id="F2"/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>150</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By 401(k) Plan</value><footnoteId id="F3"/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>74231</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Hefner Family Investors Limited Partnership</value><footnoteId id="F4"/></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>100000</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By The Community Covenant Foundation, Inc.</value><footnoteId id="F5"/></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Units of Duke Realty Limited Partnership</value></securityTitle><conversionOrExercisePrice><footnoteId id="F6"/></conversionOrExercisePrice><exerciseDate><value>1994-10-04</value></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>579506</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>579506</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Grantor Retained Annuity Trust</value><footnoteId id="F7"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Units of Duke Realty Limited Partnership</value></securityTitle><conversionOrExercisePrice><footnoteId id="F6"/></conversionOrExercisePrice><exerciseDate><value>1994-10-04</value></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>13572</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>13572</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Duke Management, Inc.</value><footnoteId id="F8"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeTransaction><securityTitle><value>Units of Duke Realty Limited Partnership</value></securityTitle><conversionOrExercisePrice><footnoteId id="F6"/></conversionOrExercisePrice><transactionDate><value>2003-08-07</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>16351</value></transactionShares><transactionPricePerShare><value>27.731</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>2004-08-07</value></exerciseDate><expirationDate><footnoteId id="F6"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>16351</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>16351</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Duke Associates No. 51 Limited Partnership</value><footnoteId id="F9"/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>19.4375</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F10"/></exerciseDate><expirationDate><value>2007-01-29</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>11966</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>11966</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>24.2500</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F11"/></exerciseDate><expirationDate><value>2008-01-28</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>18960</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>18960</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>23.0625</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F12"/></exerciseDate><expirationDate><value>2009-01-26</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>24920</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>24920</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>20.0000</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F13"/></exerciseDate><expirationDate><value>2010-01-25</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>31609</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>31609</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>24.9800</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F14"/></exerciseDate><expirationDate><value>2011-01-31</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>27608</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>27608</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>19.4375</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F10"/></exerciseDate><expirationDate><value>2007-01-29</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1044</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1044</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Family Limited Partnership</value><footnoteId id="F4"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>23.3500</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F15"/></exerciseDate><expirationDate><value>2012-01-30</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>21659</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>21659</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>25.4200</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F16"/></exerciseDate><expirationDate><value>2013-02-19</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>46913</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>46913</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Exchange Rights </value></securityTitle><conversionOrExercisePrice><footnoteId id="F17"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F17"/></exerciseDate><expirationDate><footnoteId id="F17"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>172583</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>172583</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Duke Management, Inc.</value><footnoteId id="F17"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Phantom Stock Units</value></securityTitle><conversionOrExercisePrice><footnoteId id="F18"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F18"/></exerciseDate><expirationDate><footnoteId id="F18"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>5493</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5493</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Securities held by the Thomas L. Hefner Revocable Trust in which the Reporting Person is the grantor.</footnote><footnote id="F2">Securities held by the Patty M. Hefner Revocable Trust in which the Reporting Person is the grantor.</footnote><footnote id="F3">Between May 12, 2003 and August 7, 2003, the Reporting Person acquired 35 shares of Duke Realty Corporation common stock under the Company's 401(k) plan.</footnote><footnote id="F4">Securities owned by the Hefner Family Investors Limited Partnership, a family limited partnership in which the sole general partner is the Reporting Person and the limited partnership interests are beneficially held by the Reporting Person and his family members.  All stock options held by the partnership are fully vested.</footnote><footnote id="F5">Shares owned by The Community Covenant Foundation, Inc., a private charitable foundation controlled by the Reporting Person and his family.</footnote><footnote id="F6">Units of Duke Realty Limited Partnership are convertible on a one to one basis to the Company's common stock and have no expiration date.</footnote><footnote id="F7">Securities held by the Thomas L. Hefner 2002 Grantor Retained Annuity Trust No. 2.  The Reporting Person is a trustee and the Reporting Person's children are residual beneficiaries.</footnote><footnote id="F8">Represents the Reporting Person's 20.71% interest in Units owned by Duke Management, Inc.</footnote><footnote id="F9">Represents the Reporting Person's 15.438% interest in Duke Associates No. 51 Limited Partnership.  Pursuant to Rule 16(b)-3(d) of Section 16(b) of the Securities Exchange Act of 1934 this transaction is exempt as an acquisition from the issuer with advance approval by the board of directors.</footnote><footnote id="F10">The Stock Options vested annually at a rate of 20% per year and were fully vested on 1/29/02.</footnote><footnote id="F11">The Stock Options vested annually at a rate of 20% per year and were fully vested on 1/28/03.</footnote><footnote id="F12">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/26/04.</footnote><footnote id="F13">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/25/05.</footnote><footnote id="F14">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/31/06.</footnote><footnote id="F15">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/30/07.</footnote><footnote id="F16">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 2/19/08.</footnote><footnote id="F17">In the event of a change in control of Duke Realty Corporation or Duke Realty Limited Partnership; or the liquidation of Duke Realty Limited Partnership, Duke Management, Inc. has the right to exchange its limited partnership interest in Duke Realty Services Limited Partnership for 833,334 shares of Duke Realty Corporation's common stock.  The Reporting Person's ownership interest in Duke Management, Inc. is 20.71%.</footnote><footnote id="F18">Represents phantom stock units vested under the 2000 Performance Share Plan of Duke Realty Corporation.  Between May 12, 2003 and August 7, 2003, the Reporting Person acquired 163 units through dividend reinvestment.  The units are valued on a one to one basis to the Company's common stock and are to be settled in cash upon the Reporting Person's termination of employment.</footnote></footnotes><remarks/><ownerSignature><signatureName>Thomas L. Hefner by James R. Windmiller per POA attached</signatureName><signatureDate>2003-08-08</signatureDate></ownerSignature></ownershipDocument>

