Item 5.03. Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year.

On October 31, 2012, the Board of Directors of Marathon Oil Corporation (the "Company"), acting upon the recommendation of its Corporate Governance and Nominating Committee, amended the Company's By-laws ("By-Laws"). The amendments will be effective January 1, 2013. Article I, Section 1.6, Article II, Sections 2.7 and 2.10, and Article VI, Section 6.10 of the By-laws were amended to incorporate the role of the Lead Director. Article I, Section 1.7 of the By-laws was amended to provide for the ratification of the appointment of the independent public accountants by a vote of the stockholders, if submitted for a vote of stockholders. Article II, Section 2.11 of the By-laws was amended to describe the compensation of Directors, which includes an annual cash retainer and an annual common stock unit award. The amendments also provide that the Lead Director and Board Committee chairs also receive retainers. The foregoing is merely a summary of the amendments to the By-laws and is qualified in its entirety by reference to the complete amendments to Sections 1.6, 1.7, 2.7, 2.10, 2.11 and 6.10 of the By-laws, which are attached hereto as Exhibit 3.1 and incorporated herein by reference.

9.01. Financial Statements and Exhibits

3.1 Amendments to By-laws of Marathon Oil Corporation.

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