<ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-09-30</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000007694</issuerCik><issuerName>ASHLAND INC</issuerName>        <issuerTradingSymbol>ASH</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001166070</rptOwnerCik><rptOwnerName>HALE ROGER W</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>2915 INDIGOBUSH WAY</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>NAPLES</rptOwnerCity><rptOwnerState>FL</rptOwnerState><rptOwnerZipCode>34105</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle></officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Restricted Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1000</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Common Stock Units</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F2"/></conversionOrExercisePrice><transactionDate><value>2003-09-30</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F3"/></transactionCoding><transactionAmounts><transactionShares><value>427</value></transactionShares><transactionPricePerShare><value>32.85</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F3"/></exerciseDate><expirationDate><footnoteId id="F3"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>427</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>3735</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">Represents shares of Restricted Common Stock acquired pursuant to Ashland's stock incentive plans as approved by the shareholders and exempt pursuant to Rule 16b-3.</footnote><footnote id="F2">Converts to common stock on a one-for-one basis.</footnote><footnote id="F3">Common Stock Units acquired pursuant to Ashland's Deferred Compensation Plan for Non-Employee Directors as of 9-30-03, payable in cash or stock upon termination of service and exempt under Rule 16b-3.  (One (1) Common Stock Unit in the Deferred Compensation Plan for Non-Employee Directors is the equivalent of one (1) share of Ashland Common Stock)</footnote></footnotes><ownerSignature><signatureName>M. Craig Hall</signatureName><signatureDate>2003-10-02</signatureDate></ownerSignature></ownershipDocument>

