-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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<SEC-DOCUMENT>0000101778-03-000048.txt : 20030825
<SEC-HEADER>0000101778-03-000048.hdr.sgml : 20030825
<ACCEPTANCE-DATETIME>20030825162436
ACCESSION NUMBER:		0000101778-03-000048
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20030822
FILED AS OF DATE:		20030825

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			GOLDER G DAVID
		CENTRAL INDEX KEY:			0001238370

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	033-07065
		FILM NUMBER:		03864587

	MAIL ADDRESS:	
		STREET 1:		MARATHON OIL CORP
		STREET 2:		5555 SAN FELIPE ROAD
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77056

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MARATHON OIL CORP
		CENTRAL INDEX KEY:			0000101778
		STANDARD INDUSTRIAL CLASSIFICATION:	PETROLEUM REFINING [2911]
		IRS NUMBER:				250996816
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		P O BOX 3128
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77253-3128
		BUSINESS PHONE:		7136296600

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	USX CORP
		DATE OF NAME CHANGE:	19920703

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	UNITED STATES STEEL CORP/DE
		DATE OF NAME CHANGE:	19860714
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
    <periodOfReport>2003-08-22</periodOfReport>
    <notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000101778</issuerCik>
        <issuerName>MARATHON OIL CORP</issuerName>
        <issuerTradingSymbol>MRO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001238370</rptOwnerCik>
            <rptOwnerName>GOLDER G DAVID</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MARATHON OIL CORP</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.-Commercial. and Dev.</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>
  <nonDerivativeTable>
   <nonDerivativeTransaction>
      <securityTitle>
          <value>COMMON STOCK</value>
      </securityTitle>
      <transactionDate>
          <value>2003-08-22</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>I</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
              <footnoteId id="F1" />
      </transactionCoding>
      <transactionTimeliness>
      <value />
      </transactionTimeliness>
      <transactionAmounts>
          <transactionShares>
              <value>3590.509</value>
              <footnoteId id="F2" />
          </transactionShares>
          <transactionPricePerShare>
              <value>27.13</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>D</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>27332.000</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </nonDerivativeTransaction>
  </nonDerivativeTable>
  <derivativeTable>
   <derivativeTransaction>
      <securityTitle>
          <value>Phantom Stock</value>
      </securityTitle>
      <conversionOrExercisePrice>
              <footnoteId id="F3" />
      </conversionOrExercisePrice>
      <transactionDate>
          <value>2003-08-22</value>
      </transactionDate>
      <transactionCoding>
          <transactionFormType>4</transactionFormType>
          <transactionCode>I</transactionCode>
          <equitySwapInvolved>0</equitySwapInvolved>
              <footnoteId id="F4" />
      </transactionCoding>
      <transactionAmounts>
          <transactionShares>
              <value>1161.166</value>
              <footnoteId id="F5" />
          </transactionShares>
          <transactionPricePerShare>
              <value>26.82</value>
          </transactionPricePerShare>
          <transactionAcquiredDisposedCode>
              <value>D</value>
          </transactionAcquiredDisposedCode>
      </transactionAmounts>
      <exerciseDate>
              <footnoteId id="F6" />
      </exerciseDate>
      <expirationDate>
              <footnoteId id="F7" />
      </expirationDate>
      <underlyingSecurity>
          <underlyingSecurityTitle>
              <value>COMMON STOCK</value>
          </underlyingSecurityTitle>
          <underlyingSecurityShares>
              <value>1161.166</value>
          </underlyingSecurityShares>
      </underlyingSecurity>
      <postTransactionAmounts>
          <sharesOwnedFollowingTransaction>
              <value>0.000</value>
          </sharesOwnedFollowingTransaction>
      </postTransactionAmounts>
      <ownershipNature>
          <directOrIndirectOwnership>
              <value>D</value>
          </directOrIndirectOwnership>
      </ownershipNature>
   </derivativeTransaction>
  </derivativeTable>
<footnotes>
   <footnote id="F1">Transfer out of issuer stock fund into another fund in Marathon Oil CompanyThrift Plan.</footnote>
   <footnote id="F2">Includes 31.058 shares, previously not reported, allocated to issuer stock fund for reporting person's account in Marathon Oil Co
mpany Thrift Plan. </footnote>
   <footnote id="F3">1-for-1</footnote>
   <footnote id="F4">Transfer out of issuer phantom stock fund into another fund in Marthon Oil Company Deferred Compensation Plan. </footnote>
   <footnote id="F5">Includes dividends of 21.24 shares at average weighted price of 24.81 per share, previously not reported pursuant to Rule 16a-11,
 for reporting person's phantom stock account in Marathon Oil Company Deferred Compensation Plan.</footnote>
   <footnote id="F6">Immediately</footnote>
   <footnote id="F7">Shares of Phantom Stock are payable in cash following the termination of the reporting person's employment.</footnote>
</footnotes>
    <ownerSignature>
       <signatureName>By: Richard J. Kolencik, Attorney-in-Fact for G. David Golde</signatureName>
       <signatureDate>2003-08-25</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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