<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2008-02-27</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000101778</issuerCik>
        <issuerName>MARATHON OIL CORP</issuerName>
        <issuerTradingSymbol>MRO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001239300</rptOwnerCik>
            <rptOwnerName>HOWARD JERRY</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MARATHON OIL CORPORATION</rptOwnerStreet1>
            <rptOwnerStreet2>5555 SAN FELIPE ROAD</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77056</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr. V.P., Corporate Affairs</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>COMMON STOCK</value>
            </securityTitle>
            <transactionDate>
                <value>2008-02-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>2400.000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>93613.639</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>EMPLOYEE STOCK OPTION (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>54.36</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-02-27</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>13700.00</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <value>2009-02-27</value>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2018-02-27</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>COMMON STOCK</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>13700.00</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>13700.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">Restricted Stock granted under Marathon Oil Corporation 2007 Incentive Compensation Plan, which vests on 02/27/2011.</footnote>
        <footnote id="F2">On June 18, 2007, the common stock of Marathon Oil Corporation split 2-for-1 for holders of record on May 23, 2007, resulting in
the reporting person's ownership of 45,606.075 additional shares of common stock.</footnote>
        <footnote id="F3">Vests in three cumulative annual installments of 4,566, 4,567, and 4,567 shares on February 27, 2009, 2010, and 2011, respectivel
y.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>R. J. Kolencik, Attorney-in-Fact for Jerry Howard</signatureName>
        <signatureDate>2008-02-28</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2008-02-27
0
0000101778
MARATHON OIL CORP
MRO
0001239300
HOWARD JERRY
C/O MARATHON OIL CORPORATION
5555 SAN FELIPE ROAD
HOUSTON
TX
77056
0
1
0
0
Sr. V.P., Corporate Affairs
COMMON STOCK
2008-02-27
4
A
0
2400.000
0
A
93613.639
D
EMPLOYEE STOCK OPTION (Right to Buy)
54.36
2008-02-27
4
A
0
13700.00
0
A
2009-02-27
2018-02-27
COMMON STOCK
13700.00
13700.00
D
Restricted Stock granted under Marathon Oil Corporation 2007 Incentive Compensation Plan, which vests on 02/27/2011.
On June 18, 2007, the common stock of Marathon Oil Corporation split 2-for-1 for holders of record on May 23, 2007, resulting in
the reporting person's ownership of 45,606.075 additional shares of common stock.
Vests in three cumulative annual installments of 4,566, 4,567, and 4,567 shares on February 27, 2009, 2010, and 2011, respectivel
y.
R. J. Kolencik, Attorney-in-Fact for Jerry Howard
2008-02-28