Ownership Submission
FORM 3
 UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

INITIAL STATEMENT OF BENEFICIAL OWNERSHIP OF SECURITIES

Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934, Section 17(a) of the Public Utility Holding Company Act of 1935 or Section 30(h) of the Investment Company Act of 1940
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(Print or Type Responses)
1. Name and Address of Reporting Person *
  Bay Annell R
 2. Date of Event Requiring Statement (Month/Day/Year)
01/25/2013		 3. Issuer Name and Ticker or Trading Symbol
MARATHON OIL CORP [MRO]
(Last)
(First)
(Middle)
C/O MARATHON OIL CORPORATION, 5555 SAN FELIPE STREET		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
VP-Global Exploration
 5. If Amendment, Date Original Filed(Month/Day/Year)
(Street)

HOUSTON, TX 77056		 6. Individual or Joint/Group Filing(Check Applicable Line)
_X_ Form filed by One Reporting Person
___ Form filed by More than One Reporting Person
(City)
(State)
(Zip)
Table I - Non-Derivative Securities Beneficially Owned
1.Title of Security
(Instr. 4)		 2. Amount of Securities Beneficially Owned
(Instr. 4)		 3. Ownership Form: Direct (D) or Indirect (I)
(Instr. 5)		 4. Nature of Indirect Beneficial Ownership
(Instr. 5)
Marathon Oil Corporation Common Stock 58,056
D
 

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly. SEC 1473 (7-02)
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Table II - Derivative Securities Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 4)		 2. Date Exercisable and Expiration Date
(Month/Day/Year)		 3. Title and Amount of Securities Underlying Derivative Security
(Instr. 4)		 4. Conversion or Exercise Price of Derivative Security 5. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 5)		 6. Nature of Indirect Beneficial Ownership
(Instr. 5)
Date Exercisable Expiration Date Title Amount or Number of Shares
Employee Stock Option (Right to Buy) 02/25/2011 02/25/2019 Common Stock 38,773 $ 14.92 D  
Employee Stock Option (Right to Buy) 02/25/2012 02/25/2019 Common Stock 32,500 $ 14.92 D  
Employee Stock Option (Right to Buy) 02/24/2012(1) 02/24/2020 Common Stock 74,717 $ 18.28 D  
Employee Stock Option (Right to Buy) 02/23/2012(2) 02/23/2021 Common Stock 28,525 $ 30.81 D  
Employee Stock Option (Right to Buy) 02/28/2013(3) 02/28/2022 Common Stock 27,100 $ 35.06 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Bay Annell R
C/O MARATHON OIL CORPORATION
5555 SAN FELIPE STREET
HOUSTON, TX 77056		       VP-Global Exploration  

Signatures

Richard J. Kolencik, Attorney-in-Fact for Annell R. Bay 02/01/2013
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 5(b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations. See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
(1) Vests in cumulative installments of 37,358 and 37,359 shares on February 24, 2012 and 2013, respectively.
(2) Vests in cumulative annual installments of 9,507, 9,509 and 9,509 shares on February 23, 2012, 2013 and 2014, respectively.
(3) Vests in cumulative annual installments of 9,033, 9,033 and 9,034 shares on February 28, 2013, 2014 and 2015, respectively.

Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, See Instruction 6 for procedure.

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