<ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>4</documentType><periodOfReport>2003-12-15</periodOfReport><notSubjectToSection16>0</notSubjectToSection16><issuer><issuerCik>0000007694</issuerCik><issuerName>ASHLAND INC</issuerName>        <issuerTradingSymbol>ASH</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001166069</rptOwnerCik><rptOwnerName>WATERS FRANK L</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>5200 BLAZER PARKWAY</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>DUBLIN</rptOwnerCity><rptOwnerState>OH</rptOwnerState><rptOwnerZipCode>43017</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>0</isDirector><isOfficer>1</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther><officerTitle>Vice President</officerTitle><otherText></otherText></reportingOwnerRelationship></reportingOwner><nonDerivativeTable><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>149</value><footnoteId id="F1"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>1601</value><footnoteId id="F2"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>401(k)</value></natureOfOwnership></ownershipNature></nonDerivativeHolding><nonDerivativeHolding><securityTitle><value>Common Stock</value></securityTitle><postTransactionAmounts><sharesOwnedFollowingTransaction><value>670</value><footnoteId id="F3"/></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>I</value></directOrIndirectOwnership><natureOfOwnership><value>LESOP</value></natureOfOwnership></ownershipNature></nonDerivativeHolding></nonDerivativeTable><derivativeTable><derivativeTransaction><securityTitle><value>Common Stock Units</value></securityTitle><conversionOrExercisePrice><value>0</value><footnoteId id="F4"/></conversionOrExercisePrice><transactionDate><value>2003-12-15</value></transactionDate><deemedExecutionDate></deemedExecutionDate><transactionCoding><transactionFormType>4</transactionFormType><transactionCode>J</transactionCode><equitySwapInvolved>0</equitySwapInvolved><footnoteId id="F5"/></transactionCoding><transactionAmounts><transactionShares><value>125</value></transactionShares><transactionPricePerShare><value>41.67</value></transactionPricePerShare><transactionAcquiredDisposedCode><value>A</value></transactionAcquiredDisposedCode></transactionAmounts><exerciseDate><footnoteId id="F5"/></exerciseDate><expirationDate><footnoteId id="F5"/></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>125</value></underlyingSecurityShares></underlyingSecurity><postTransactionAmounts><sharesOwnedFollowingTransaction><value>25069</value></sharesOwnedFollowingTransaction></postTransactionAmounts><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership><natureOfOwnership><value></value></natureOfOwnership></ownershipNature></derivativeTransaction></derivativeTable><footnotes><footnote id="F1">20 of these shares are held in Ashland's  Open Enrollment Dividend Reinvestment and Stock Purchase Plan as of 9-15-03.</footnote><footnote id="F2">Based on Employee Savings Plan information as of 12-15-03, the latest date for which such information is reasonably available.</footnote><footnote id="F3">Shares accrued under Ashland's Leveraged Employee Stock Ownership Plan as of 11-30-03.</footnote><footnote id="F4">1-for-1</footnote><footnote id="F5">Common Stock Units acquired pursuant to Ashland's 1995 Deferred Compensation Plan as of 12-15-03,  payable in cash or stock upon termination of service and exempt under Rule 16b-3.  (One (1) Common Stock Unit in the 1995 Deferred Compensation Plan is the equivalent of one (1) share of Ashland Common Stock)</footnote></footnotes><ownerSignature><signatureName>M. Craig Hall</signatureName><signatureDate>2003-12-17</signatureDate></ownerSignature></ownershipDocument>

