Ownership Submission
FORM 4
Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).
UNITED STATES SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

STATEMENT OF CHANGES IN 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
OMB APPROVAL
OMB Number: 3235-0287
Expires: January 31, 2005
Estimated average burden hours per response... 0.5

(Print or Type Responses)
1. Name and Address of Reporting Person *
HOWARD JERRY
   2. Issuer Name and Ticker or Trading Symbol
MARATHON OIL CORP [MRO] 		5. Relationship of Reporting Person(s) to Issuer
(Check all applicable)
_____ Director _____ 10% Owner
__X__ Officer (give title below) _____ Other (specify below)
Sr. V.P., Corporate Affairs
(Last)
(First)
(Middle)
C/O MARATHON OIL CORPORATION, 5555 SAN FELIPE ROAD		 3. Date of Earliest Transaction (Month/Day/Year)
05/16/2005
(Street)

HOUSTON, TX 77056		 4. If Amendment, Date Original Filed(Month/Day/Year)
 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 Acquired, Disposed of, or Beneficially Owned
1.Title of Security
(Instr. 3)		 2. Transaction Date (Month/Day/Year) 2A. Deemed Execution Date, if any (Month/Day/Year) 3. Transaction Code
(Instr. 8)		 4. Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4 and 5)		 5. Amount of Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 3 and 4)		 6. Ownership Form: Direct (D) or Indirect (I)
(Instr. 4)		 7. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V Amount (A) or (D) Price
COMMON STOCK 05/16/2005   M   7,000 A $ 29.375 54,051.467 D  
COMMON STOCK 05/16/2005   D   5,594 D $ 49.1 (1) 48,457.467 D  
COMMON STOCK 05/16/2005   M   9,000 A $ 34 57,457.467 D  
COMMON STOCK 05/16/2005   D   7,617 D $ 49.1 (1) 49,840.467 D  
COMMON STOCK 05/16/2005   M   9,750 A $ 29.375 59,590.467 D  
COMMON STOCK 05/16/2005   D   7,792 D $ 49.1 (1) 51,798.467 D  
COMMON STOCK 05/16/2005   M   16,250 A $ 32.52 68,048.467 D  
COMMON STOCK 05/16/2005   D   13,507 D $ 49.1 (1) 54,541.467 D  
COMMON STOCK 05/16/2005   M   21,000 A $ 28.12 75,541.467 D  
COMMON STOCK 05/16/2005   D   16,514 D $ 49.1 (1) 59,027.467 D  

Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB control number. SEC 1474 (9-02)

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned
(e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security
(Instr. 3)		 2. Conversion or Exercise Price of Derivative Security 3. Transaction Date (Month/Day/Year) 3A. Deemed Execution Date, if any (Month/Day/Year) 4. Transaction Code
(Instr. 8)		 5. Number of Derivative Securities Acquired (A) or Disposed of (D)
(Instr. 3, 4, and 5)		 6. Date Exercisable and Expiration Date
(Month/Day/Year)		 7. Title and Amount of Underlying Securities
(Instr. 3 and 4)		 8. Price of Derivative Security
(Instr. 5)		 9. Number of Derivative Securities Beneficially Owned Following Reported Transaction(s)
(Instr. 4)		 10. Ownership Form of Derivative Security: Direct (D) or Indirect (I)
(Instr. 4)		 11. Nature of Indirect Beneficial Ownership
(Instr. 4)
Code V (A) (D) Date Exercisable Expiration Date Title Amount or Number of Shares
Employee Stock Option (Right to Buy) $ 29.375 05/16/2005   M(2)     7,000 05/27/1998 05/27/2007 COMMON STOCK 7,000 $ 0 0 D  
STOCK APPRECIATION RIGHT $ 29.375 05/16/2005   M(2)     7,000 05/27/1998 05/27/2007 COMMON STOCK 7,000 $ 0 0 D  
EMPLOYEE STOCK OPTION (Right to Buy) $ 34 05/16/2005   M(2)     9,000 05/26/1999 05/26/2008 COMMON STOCK 9,000 $ 0 0 D  
STOCK APPRECIATION RIGHT $ 34 05/16/2005   M(2)     9,000 05/26/1999 05/26/2008 COMMON STOCK 9,000 $ 0 0 D  
EMPLOYEE STOCK OPTION (Right to Buy) $ 29.375 05/16/2005   M(2)     9,750 05/25/2000 05/25/2009 COMMON STOCK 9,750 $ 0 0 D  
STOCK APPRECIATION RIGHT $ 29.375 05/16/2005   M(2)     9,750 05/25/2000 05/25/2009 COMMON STOCK 9,750 $ 0 0 D  
EMPLOYEE STOCK OPTION (Right to Buy) $ 32.52 05/16/2005   M(2)     16,250 05/29/2002 05/29/2011 COMMON STOCK 16,250 $ 0 0 D  
STOCK APPRECIATION RIGHT $ 32.52 05/16/2005   M(2)     16,250 05/29/2002 05/29/2011 COMMON STOCK 16,250 $ 0 0 D  
EMPLOYEE STOCK OPTION (Right to Buy) $ 28.12 05/16/2005   M(2)     21,000 05/28/2003 05/28/2012 COMMON STOCK 21,000 $ 0 0 D  
STOCK APPRECIATION RIGHT $ 28.12 05/16/2005   M(2)     21,000 05/28/2003 05/28/2012 COMMON STOCK 21,000 $ 0 0 D  

Reporting Owners

Reporting Owner Name / Address Relationships
 Director  10% Owner  Officer  Other
HOWARD JERRY
C/O MARATHON OIL CORPORATION
5555 SAN FELIPE ROAD
HOUSTON, TX 77056		       Sr. V.P., Corporate Affairs  

Signatures

 Richard J. Kolencik, Attorney-in-Fact for Jerry Howard   05/18/2005
**Signature of Reporting Person Date

Explanation of Responses:

* If the form is filed by more than one reporting person, see Instruction 4(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) Under the terms of the Stock Appreciation Right, the Stock Appreciation Right price is the highest fair market value of Marathon Oil Corporation common stock during the ten day trading period commencing May 3, 2005. The highest fair market value during such ten day trading period was $49.10.
(2) Exercise of tandem SAR and cancellation of underlying stock option.

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

Potential persons who are to respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB number.