<SUBMISSION>
<ACCESSION-NUMBER>0001140361-08-020091
<TYPE>4
<PUBLIC-DOCUMENT-COUNT>1
<PERIOD>20080822
<FILING-DATE>20080822
<DATE-OF-FILING-DATE-CHANGE>20080822
<ISSUER>
<COMPANY-DATA>
<CONFORMED-NAME>CENTENE CORP
<CIK>0001071739
<ASSIGNED-SIC>6324
<IRS-NUMBER>041406317
</COMPANY-DATA>
<BUSINESS-ADDRESS>
<STREET1>7711 CARONDELET AVE
<CITY>ST LOUIS
<STATE>MO
<ZIP>63105
<PHONE>3147254477
</BUSINESS-ADDRESS>
<MAIL-ADDRESS>
<STREET1>7711 CARONDELET AVE
<STREET2>SUITE 800
<CITY>ST LOUIS
<STATE>MO
<ZIP>63105
</MAIL-ADDRESS>
</ISSUER>
<REPORTING-OWNER>
<OWNER-DATA>
<CONFORMED-NAME>SLUSSER ERIC
<CIK>0001272264
</OWNER-DATA>
<FILING-VALUES>
<FORM-TYPE>4
<ACT>34
<FILE-NUMBER>001-31826
<FILM-NUMBER>081034933
</FILING-VALUES>
<BUSINESS-ADDRESS>
<STREET1>22001 LOUDOUN COUNTY PARKWAY
<CITY>ASHBURN
<STATE>VA
<ZIP>20147
<PHONE>7038865055
</BUSINESS-ADDRESS>
</REPORTING-OWNER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-08-22</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001071739</issuerCik>
        <issuerName>CENTENE CORP</issuerName>
        <issuerTradingSymbol>CNC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001272264</rptOwnerCik>
            <rptOwnerName>SLUSSER ERIC</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>7711 CARONDELET AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>ST. LOUIS</rptOwnerCity>
            <rptOwnerState>MO</rptOwnerState>
            <rptOwnerZipCode>63105</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Executive VP &amp; CFO</officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>45000</value>
                    <footnoteId id="F1"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>0</value>
                <footnoteId id="F2"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-08-22</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>53.513</value>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>22.64</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2008-08-22</value>
            </exerciseDate>
            <expirationDate>
                <value>2008-08-22</value>
                <footnoteId id="F4"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>53.513</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2062.823</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Common Stock Option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>21.97</value>
            </conversionOrExercisePrice>
            <exerciseDate>
                <value>2012-07-09</value>
            </exerciseDate>
            <expirationDate>
                <value>2017-07-09</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>75000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>75000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Mr. Slusser's ownership includes awards of 40,000 restricted stock units subject to vesting requirements.</footnote>
        <footnote id="F2">Each share of phantom stock represents the right to receive the fair market value of one share of Centene common stock.</footnote>
        <footnote id="F3">The phantom stock was acquired by Mr. Slusser through regular scheduled payroll contributions to the Company's deferred compensation plan.</footnote>
        <footnote id="F4">The phantom stock has no formal expiration date.  The phantom stock will be settled in cash or other non-Company securities upon Mr. Slusser's termination with the Company or on such other date Mr. Slusser may elect.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Eric R. Slusser</signatureName>
        <signatureDate>2008-08-22</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SUBMISSION>
