<SUBMISSION>
<ACCESSION-NUMBER>0000007694-04-000194
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20041215
<FILING-DATE>20041216
<DATE-OF-FILING-DATE-CHANGE>20041216
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ASHLAND INC
<CIK>0000007694
<ASSIGNED-SIC>5160
<IRS-NUMBER>610122250
<STATE-OF-INCORPORATION>KY
<FISCAL-YEAR-END>0930
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>50 E. RIVERCENTER BOULEVARD
<CITY>COVINGTON
<STATE>KY
<ZIP>41012
<PHONE>6068153333
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>50 E. RIVERCENTER BOULEVARD
<CITY>COVINGTON
<STATE>KY
<ZIP>41012
</MAIL-ADDRESS>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ASHLAND OIL INC
<DATE-CHANGED>19920703
</FORMER-COMPANY>
<FORMER-COMPANY>
<FORMER-CONFORMED-NAME>ASHLAND OIL & REFINING CO
<DATE-CHANGED>19700806
</FORMER-COMPANY>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>QUIN J MARVIN
<CIK>0001023536
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-02918
<FILM-NUMBER>041209237
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>PO BOX 391
<CITY>ASHLAND
<STATE>KY
<ZIP>41114
<PHONE>6063293333
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>C/O ASHLAND INC
<STREET2>1000 ASHLAND DRIVE PO BOX 391
<CITY>RUSSELL
<STATE>KY
<ZIP>41169
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001023536d20041216f4s1f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-12-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000007694</issuerCik>
        <issuerName>ASHLAND INC</issuerName>
        <issuerTradingSymbol>ASH</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001023536</rptOwnerCik>
            <rptOwnerName>QUIN J MARVIN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>50 E. RIVERCENTER BOULEVARD</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>COVINGTON</rptOwnerCity>
            <rptOwnerState>KY</rptOwnerState>
            <rptOwnerZipCode>41012-0391</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chief Financial Officer</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>27533</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>7032</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>LESOP</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2440</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401(K)</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Common Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F3"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-12-15</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>J</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F4"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>253</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>58.23</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>253</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>76360</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Shares accrued under Ashland's Leveraged Employee Stock Ownership Plan as of 11-30-04.</footnote>
        <footnote id="F2">Based on Employee Savings Plan information as of 12-14-04, the latest date for which such information is reasonably available.</footnote>
        <footnote id="F3">1-for-1</footnote>
        <footnote id="F4">Common Stock Units acquired pursuant to Ashland's 1995 Deferred Compensation Plan as of 12-15-04, and exempt under Rule 16b-3(d).  (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>2004-12-16</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
