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 *
  Guidry Steven P
 2. Date of Event Requiring Statement (Month/Day/Year)
07/01/2011		 3. Issuer Name and Ticker or Trading Symbol
MARATHON OIL CORP [MRO]
(Last)
(First)
(Middle)
C/O MARATHON OIL CORPORATION, 5555 SAN FELIPE RD.		 4. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
V.P. - Business Development
 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 12,753.068
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
Stock Appreciation Right 05/26/2007 05/26/2014 Common Stock 1,270 $ 10.53 D  
Employee Stock Option (Right to Buy) 06/10/2008 06/10/2015 Common Stock 6,568 $ 16.19 D  
Employee Stock Option (Right to Buy) 06/01/2009 06/01/2016 Common Stock 7,840 $ 23.69 D  
Employee Stock Option (Right to Buy) 05/30/2010 05/30/2017 Common Stock 15,233 $ 38.25 D  
Employee Stock Option (Right to Buy) 05/28/2011 05/28/2018 Common Stock 11,450 $ 32.06 D  
Employee Stock Option (Right to Buy) 05/27/2012 05/27/2019 Common Stock 11,705 $ 18.32 D  
Employee Stock Option (Right to Buy) 05/26/2011(1) 05/26/2020 Common Stock 23,412 $ 19.03 D  
Employee Stock Option (Right to Buy) 05/25/2012(2) 05/25/2021 Common Stock 33,705 $ 33.06 D  

Reporting Owners

Reporting Owner Name / Address Relationships
Director 10% Owner Officer Other
Guidry Steven P
C/O MARATHON OIL CORPORATION
5555 SAN FELIPE RD.
HOUSTON, TX 77056		       V.P. - Business Development  

Signatures

Yvonne R. Kunetka, Attorney-in-Fact for Steven P. Guidry 07/06/2011
**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 annual installments of 11,705 and 11,707 shares on May 26, 2012 and 2013, respectively.
(2) Vests in three cumulative annual installments of 11,235, 11,235 and 11,235 on May 25, 2012, 2013, and 2014, respectively.

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