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

    <documentType>4</documentType><periodOfReport>2003-10-29</periodOfReport>
    <issuer>
        <issuerCik>0001110805</issuerCik>
        <issuerName>VALERO L P</issuerName>
        <issuerTradingSymbol>VLI</issuerTradingSymbol></issuer><reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001220165</rptOwnerCik>
            <rptOwnerName>MCVICKER JERRY D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>P.O. BOX 500</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN ANTONIO</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>78292-0500</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
            <reportingOwnerRelationship>
<isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Vice President</officerTitle></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeTransaction><securityTitle><value>Common Units</value></securityTitle><transactionDate><value>2003-10-29</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>590</value><footnoteId id="F1"/></transactionShares><transactionPricePerShare><value>0</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2090</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></nonDerivativeTransaction></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Employee Unit Options (right to buy)</value></securityTitle><conversionOrExercisePrice><value>45.35</value></conversionOrExercisePrice><transactionDate><value>2003-10-29</value></transactionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>A</transactionCode><equitySwapInvolved>0</equitySwapInvolved></transactionCoding><transactionAmounts><transactionShares><value>2875</value></transactionShares><transactionPricePerShare><footnoteId id="F3"/></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F2"/></exerciseDate><expirationDate><value>2013-10-29</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Units</value></underlyingSecurityTitle><underlyingSecurityShares><value>2875</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>2875</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value/></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Award of restricted units.  The restricted units vest annually in equal increments over a five-year period beginning in October 2004.</footnote><footnote id="F2">The unit options vest annually in equal increments over a five-year period beginning in October 2004.</footnote><footnote id="F3">The derivative security did not have a purchase price.</footnote></footnotes><remarks/><ownerSignature><signatureName>Jerry D. McVicker</signatureName><signatureDate>2003-10-30</signatureDate></ownerSignature></ownershipDocument>

