<SUBMISSION>
<ACCESSION-NUMBER>0000945094-04-000730
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20041201
<FILING-DATE>20041203
<DATE-OF-FILING-DATE-CHANGE>20041203
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>ALLSTATE CORP
<CIK>0000899051
<ASSIGNED-SIC>6331
<IRS-NUMBER>363871531
<STATE-OF-INCORPORATION>DE
<FISCAL-YEAR-END>1231
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>2775 SANDERS ROAD
<CITY>NORTHBROOK
<STATE>IL
<ZIP>60062
<PHONE>8474025000
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>2775 SANDERS ROAD
<CITY>NORTHBROOK
<STATE>IL
<ZIP>60062
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>SPRIESER JUDITH A
<CIK>0001206994
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-11840
<FILM-NUMBER>041182581
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>TRANSORA,
<STREET2>10 S. RIVERSIDE PLZ. #2000
<CITY>CHICAGO
<STATE>IL
<ZIP>60606
<PHONE>3124634350
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>TRANSORA
<STREET2>10 S. RIVERSIDE PLZ. #2000
<CITY>CHICAGO
<STATE>IL
<ZIP>60606
</MAIL-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>c0001206994d20041203f4f.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-12-01</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000899051</issuerCik>
        <issuerName>ALLSTATE CORP</issuerName>
        <issuerTradingSymbol>ALL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001206994</rptOwnerCik>
            <rptOwnerName>SPRIESER JUDITH A</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>TRANSORA</rptOwnerStreet1>
            <rptOwnerStreet2>10 S. RIVERSIDE PLAZA, SUITE 2000</rptOwnerStreet2>
            <rptOwnerCity>CHICAGO</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60606</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable></nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Restricted Stock Units</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F1"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-12-01</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>2000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted Stock Units (RSUs) are granted under The Allstate Corporation Equity Incentive Plan for Non-Employee Directors, as Amended and Restated effective as of November 9, 2004.  Each RSU represents the right to receive one share of Allstate common stock upon the earlier of (i) the date of the reporting person's death or disability, and (ii) one year after the date on which the reporting person is no longer serving as a director of Allstate.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>Katherine A. Smith for Judith A. Sprieser</signatureName>
        <signatureDate>2004-12-03</signatureDate>
    </ownerSignature>
</ownershipDocument>

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