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

    <documentType>4/A</documentType><periodOfReport>2003-06-23</periodOfReport><dateOfOriginalSubmission>2003-06-16</dateOfOriginalSubmission>
    <issuer>
        <issuerCik>0000030554</issuerCik>
        <issuerName>DUPONT E I DE NEMOURS &amp; CO</issuerName>
        <issuerTradingSymbol>dd</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId>
            <rptOwnerCik>0001127286</rptOwnerCik>
            <rptOwnerName>CONNELLY THOMAS M JR</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>  </rptOwnerStreet1>
            <rptOwnerStreet2>  </rptOwnerStreet2>
            <rptOwnerCity>  </rptOwnerCity>
            <rptOwnerState>  </rptOwnerState>
            <rptOwnerZipCode>  </rptOwnerZipCode>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Sr. Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><derivativeSecurity><securityTitle><value>DuPont Common Stock Units</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F1"/></conversionOrExercisePrice><transactionDate><value>2003-06-12</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F2"/></transactionCoding><transactionAmounts><transactionShares><value>27.3976</value></transactionShares><transactionValue><value>44.14</value></transactionValue><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><value>1988-08-08</value></exerciseDate><expirationDate><value>1988-08-08</value><footnoteId id="F3"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>27.3976</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3482.6341</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeSecurity><footnotes><footnote id="F1">Units convert one-for-one to DuPont common stock.</footnote><footnote id="F2">Dividend equivalents credited as stock units under the DuPont Variable Compensation Plan.</footnote><footnote id="F3"> Units become payable in common stock at the election of the reporting person.</footnote></footnotes><ownerSignature><signatureName>Thomas M. Connelly, Jr. by Mary E. Bowler</signatureName><signatureDate>2003-06-23</signatureDate></ownerSignature></ownershipDocument>

