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| (Mark One) |                                                                                   |
|------------|----------------------------------------------------------------------------------------|
| [X]        | QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 |
|       | For the Quarterly Period Ended March 31, 2011                                          |

| [   ] | TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d)OF THE SECURITIES EXCHANGE ACT OF 1934 |
|----------------------|-----------------------------------------------------------------------------------------|
|                 | For the transition period from _____ to _____                                           |

| Delaware                                                       | 25-0996816                           |
|----------------------------------------------------------------|--------------------------------------|
| (State or other jurisdiction of incorporation or organization) | (I.R.S. Employer Identification No.) |

| Large accelerated filer  þ                                                                                                                     | Accelerated filer               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|---------------------------------------------------------------------------------------------|
| Non-accelerated filer               (Do not check if a smaller reporting company)  | Smaller reporting company            |

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| Exhibit Number |                |                                                                                                                                                    |   | Incorporated by Reference |    | Filed Herewith |        | Furnished Herewith |
|----------------|---------------------|---------------------------------------------------------------------------------------------------------------------------------------------------------|--------|---------------------------|---------|----------------|-------------|--------------------|
|           | Exhibit Description |                                                                                                                                                    | Form   |                      | Exhibit |           | Filing Date |               | SEC File No. |   |   |
|           |                |                                                                                                                                                    |   |                      |    |           |        |               |   |   |   |   |   |   |
| 3.1       |                | Amended By-laws of Marathon Oil Corporation                                                                                                             |   |                      |    |           |        |               |   |   |   | X |   |   |
|           |                |                                                                                                                                                    |   |                      |    |           |        |               |   |   |   |   |   |   |
| 12.1      |                | Computation of Ratio of Earnings to Fixed Charges.                                                                                                      |   | 10-Q                      |    |  12.1     |        | 05/06/2011         |   |   |   |   |   |   |
|           |                |                                                                                                                                                    |   |                      |    |           |        |               |   |   |   |   |   |   |
| 31.1      |                | Certification of President and Chief Executive Officer pursuant to Rule 13(a)-14 and 15(d)-14 under the Securities Exchange Act of 1934.                |   | 10-Q                      |    |  31.1     |        | 05/06/2011         |   |   |   |   |   |   |
| 31.2      |                | Certification of Executive Vice President and Chief Financial Officer pursuant to Rule 13(a)-14 and 15(d)-14 under the Securities Exchange Act of 1934. |   | 10-Q                      |    |  31.2     |        | 05/06/2011         |   |   |   |   |   |   |
| 32.1      |                | Certification of President and Chief Executive Officer pursuant to 18 U.S.C. Section 1350.                                                              |   | 10-Q                      |    |  32.1     |        | 05/06/2011         |   |   |   |   |   |   |
| 32.2      |                | Certification of Executive Vice President and Chief Financial Officer pursuant to 18 U.S.C. Section 1350.                                               |   | 10-Q                      |    | 32.2           |        | 05/06/2011         |   |   |   |   |   |   |
|           |                |                                                                                                                                                    |   |                      |    |           |        |               |   |   |   |   |   |   |
| 101.INS        |                | XBRL Instance Document.                                                                                                                                 |   | 10-Q                      |    | 101.INS        |        | 05/06/2011         |   |   |   |   |   |   |
| 101.SCH        |                | XBRL Taxonomy Extension Schema.                                                                                                                         |   | 10-Q                      |    |  101.SCH  |        | 05/06/2011         |   |   |   |   |   |   |
| 101.PRE        |                | XBRL Taxonomy Extension Presentation Linkbase.                                                                                                          |   | 10-Q                      |    |  101.PRE  |        | 05/06/2011         |   |   |   |   |   |   |
| 101.CAL        |                | XBRL Taxonomy Extension Calculation Linkbase.                                                                                                           |   | 10-Q                      |    |  101.CAL  |        | 05/06/2011         |   |   |   |   |   |   |
| 101.DEF        |                | XBRL Taxonomy Extension Definition Linkbase.                                                                                                            |   | 10-Q                      |    |  101.DEF  |        | 05/06/2011         |   |   |   |   |   |   |
| 101.LAB        |                | XBRL Taxonomy Extension Label Linkbase.                                                                                                                 |   | 10-Q                      |    |  101.LAB  |        | 05/06/2011         |   |   |   |   |   |   |
|           |                |                                                                                                                                                    |   |                      |    |           |        |               |   |   |   |   |   |   |

| May 13, 2011 | MARATHON OIL CORPORATION                  |
|--------------|-------------------------------------------|
|         |                                      |
|         | By: /s/  Michael K. Stewart     |
|         | Michael K. Stewart                        |
|         | Vice President, Accounting and Controller |