<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0101</schemaVersion>

<documentType>4</documentType><periodOfReport>2003-05-12</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>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
<reportingOwnerRelationship>
<isDirector>1</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Chairman &amp;amp; CEO</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-02-28</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>54</value></transactionShares><transactionValue><value>25.95</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>115</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By 401(k) Plan</value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><nonDerivativeSecurity><securityTitle><value>Common Stock</value></securityTitle><transactionDate><value>2003-05-12</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>S</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>5000</value></transactionShares><transactionValue><value>28.1</value></transactionValue><transactionAcquiredDisposedCode><value>D</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>74231</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>By Family Owned L.P.</value></natureOfOwnership></ownershipNature></nonDerivativeSecurity><derivativeSecurity><securityTitle><value>Phantom Stock Units</value><footnoteId id="F3"/></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F3"/></conversionOrExercisePrice><transactionDate><value>2003-02-28</value></transactionDate><transactionCoding><transactionFormType>5</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>175</value></transactionShares><transactionValue><value>25.95</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1988-08-08</value><footnoteId id="F3"/></exerciseDate><expirationDate><value>1988-08-08</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>175</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>5330</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">Represents purchases and dividend reinvestments accrued through the Company 401(k) plan per plan statement dated May 12, 2003. </footnote><footnote id="F2">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.</footnote><footnote id="F3">Represents phantom stock units accrued through dividend reinvestment equivalents under the 2000 Performance Share Plan of Duke Realty Corporation.  The units are to be settled in cash upon the Reporting Person's termination of employment.</footnote></footnotes><ownerSignature><signatureName>Thomas L. Hefner by James R. Windmiller per POA prev. filed</signatureName><signatureDate>2003-05-13</signatureDate></ownerSignature></ownershipDocument>

