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

    <documentType>4</documentType><periodOfReport>2003-12-09</periodOfReport>
    <issuer>
        <issuerCik>0000783280</issuerCik>
        <issuerName>DUKE REALTY CORP</issuerName>
        <issuerTradingSymbol>DRE</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001024253</rptOwnerCik>
            <rptOwnerName>BURK GARY A</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>Vice Chair., EVP Construction</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-09</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1558</value></transactionShares><transactionPricePerShare><value>19.4375</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>122497</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-09</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8537</value></transactionShares><transactionPricePerShare><value>24.25</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>131034</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeTransaction><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-12-09</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>F</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>7568</value></transactionShares><transactionPricePerShare><value>31.35</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>123466</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5936</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By 401(k) Plan</value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeHolding><securityTitle><value>Units of Duke Realty Limited Partnership</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F3"/></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>90015</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>90015</value><footnoteId id="F4"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Units of Duke Realty Limited Partnership</value></securityTitle><conversionOrExercisePrice><footnoteId id="F2"/></conversionOrExercisePrice><exerciseDate><value>1994-10-04</value></exerciseDate><expirationDate><footnoteId id="F2"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>4922</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>4922</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Duke Management, Inc.</value><footnoteId id="F5"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>15.3125</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F6"/></exerciseDate><expirationDate><value>2005-10-25</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>452</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>452</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>16.0625</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F7"/></exerciseDate><expirationDate><value>2006-01-31</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>6654</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>6654</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeTransaction><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>19.4375</value></conversionOrExercisePrice><transactionDate><value>2003-12-09</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>1558</value></transactionShares><transactionPricePerShare><value>19.4375</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F8"/></exerciseDate><expirationDate><value>2007-01-29</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>1558</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5220</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeTransaction><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>24.2500</value></conversionOrExercisePrice><transactionDate><value>2003-12-09</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>M</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>8537</value></transactionShares><transactionPricePerShare><value>24.25</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F9"/></exerciseDate><expirationDate><value>2008-01-28</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>8537</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5683</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction><derivativeHolding><securityTitle><value>Employee Stock Options-Right to Buy</value></securityTitle><conversionOrExercisePrice><value>23.0625</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F10"/></exerciseDate><expirationDate><value>2009-01-26</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>19936</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>19936</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="F11"/></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="F12"/></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>23.3500</value></conversionOrExercisePrice><exerciseDate><footnoteId id="F13"/></exerciseDate><expirationDate><value>2012-01-30</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>29536</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>29536</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="F14"/></exerciseDate><expirationDate><value>2013-02-19</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>34184</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>34184</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Exchange Rights </value></securityTitle><conversionOrExercisePrice><footnoteId id="F15"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F15"/></exerciseDate><expirationDate><footnoteId id="F15"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>62583</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>62583</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Duke Management, Inc.</value><footnoteId id="F15"/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Phantom Stock Units</value></securityTitle><conversionOrExercisePrice><footnoteId id="F16"/></conversionOrExercisePrice><exerciseDate><footnoteId id="F16"/></exerciseDate><expirationDate><footnoteId id="F16"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>8098</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>8098</value><footnoteId id="F16"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding><derivativeHolding><securityTitle><value>Phantom Stock Units</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>3071</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3071</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">Between August 8, 2003 and December 10, 2003, the Reporting Person acquired 226 shares of DRE's common stock under the Company's 401(k) plan.</footnote><footnote id="F2">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="F3">The date on which 85,778 of these units were exercisable was October 4, 1994.  The date on which 4,237 units will be exercisable is August 7, 2004.</footnote><footnote id="F4">Includes 4,237 units formerly reported as an indirect holding representing a 4% interest in Duke Associates No. 51 Limited Partnership and now held directly by the Reporting Person.</footnote><footnote id="F5">Represents the Reporting Person's 7.51% interest in Units owned by Duke Management, Inc.</footnote><footnote id="F6">The Stock Options vested annually at a rate of 20% per year and were fully vested on 10/25/00.</footnote><footnote id="F7">The Stock Options vested annually at a rate of 20% per year and were fully vested on 1/31/01.</footnote><footnote id="F8">The Stock Options vested annually at a rate of 20% per year and were fully vested on 1/29/02.</footnote><footnote id="F9">The Stock Options vested annually at a rate of 20% per year and were fully vested on 1/28/03.</footnote><footnote id="F10">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/26/04.</footnote><footnote id="F11">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/25/05.</footnote><footnote id="F12">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/31/06.</footnote><footnote id="F13">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 1/30/07.</footnote><footnote id="F14">The Stock Options vest annually at a rate of 20% per year and will be fully vested on 2/19/08.</footnote><footnote id="F15">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 7.51%.</footnote><footnote id="F16">Represents phantom stock units accrued under the Executive Deferred Compensation Plan of Duke Realty Services Limited Partnership.  Between August 8, 2003 and December 10, 2003, the Reporting Person acquired 249 phantom stock 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><footnote id="F17">Represents phantom stock units vested under the 2000 Performance Share Plan of Duke Realty Corporation. 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>James R. Windmiller for Gary A. Burk per POA prev. filed</signatureName><signatureDate>2003-12-11</signatureDate></ownerSignature></ownershipDocument>

