8-K

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT

Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934

Date of Report (Date of earliest event reported): July 7, 2004

MARATHON OIL CORPORATION

(Exact name of registrant as specified in its charter)

Delaware	1-5153	25-0996816
(State or other jurisdiction of incorporation)	(Commission File Number)	(IRS Employer Identification No.)

5555 San Felipe Road, Houston, Texas	77056-2723
(Address of principal executive offices)	(Zip Code)

Registrant's telephone number, including area code: (713) 629-6600

______________________________

Item 7.	Financial Statements and Exhibits.
	(c) Exhibits.
	99.1 Press Release dated July 7, 2004, titled "Marathon Updates Guidance On Items Expected To Impact Second Quarter 2004 Financial Results."
Item 12.	Disclosure of Results of Operations and Financial Condition.
	On July 7, 2004, Marathon Oil Corporation (Marathon) issued a press release titled "Marathon Updates Guidance On Items Expected To Impact Second Quarter 2004 Financial Results." The press release is being furnished as an exhibit to this report and is incorporated herein by reference.

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

MARATHON OIL CORPORATION

Date: July 7, 2004	By:	/s/ A.G. Adkins
		A.G. Adkins
		Vice President-Accounting and Controller

EXHIBIT INDEX

Number	Exhibit
99.1	Press Release dated July 7, 2004, titled "Marathon Updates Guidance On Items Expected To Impact Second Quarter 2004 Financial Results."

EX-99.1

Exhibit 99.1

MARATHON UPDATES GUIDANCE ON ITEMS

EXPECTED TO IMPACT SECOND QUARTER 2004 FINANCIAL RESULTS

HOUSTON, July 7, 2004 -- Marathon Oil Corporation (NYSE: MRO) today announced that it is providing updated guidance and information on certain other items that may not be fully reflected in third party estimates of the company's second quarter 2004 financial results. This guidance specifically relates to:

• A non-cash mark-to-market loss on two long-term gas sales contracts in the U.K.
• An update to the company's production estimates for the second quarter and full year 2004
• Second quarter exploration expenses
• Second quarter unallocated administrative expense

U.K. Mark-to-Market Loss

During the second quarter, the U.K. 18 month forward gas price curve strengthened more than 30 percent. As a result, and as required by generally accepted accounting principles, a non-cash mark-to-market charge of approximately $95 million will be recorded in the second quarter related to two long-term sales contracts for gas produced from the Brae Area complex in the U.K. North Sea.

Revised Production Estimate

Marathon estimates that its worldwide production during the second quarter will average approximately 341,000 barrels of oil equivalent per day (boepd) compared to previous guidance of 348,000 boepd. For the full year 2004, the company estimates it will average approximately 360,000 boepd, compared to previous estimates of approximately 365,000 boepd. This reduction is primarily a result of delays associated with the company's liquids expansion projects in Equatorial Guinea. While the commissioning of the phase 2A and 2B expansion projects is taking longer than anticipated, the peak rate of 79,000 boepd (44,500 net to Marathon) is still expected to be achieved during the first half of 2005.

Exploration Expense

Second quarter exploration expense is expected to be at the lower end of the previously estimated range of $35-60 million.

Unallocated Administrative Expense

Administrative expenses in the second quarter are expected to be approximately $85-95 million, as compared to previous guidance of $62 million. This increase is primarily attributable to costs related to recently announced outsourcing activities, as well as an increase of more than $4.00 per share in Marathon's common stock price during the quarter, resulting in a non-cash charge related to equity based compensation granted to employees under approved compensation plans.

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This release contains forward-looking statements with respect to the timing and levels of the company's worldwide liquid hydrocarbon, natural gas and condensate production, the Phase 2B LPG expansion project, an estimated U.K. mark-to-market loss, and estimated exploration and administrative expenses. Some factors that could potentially affect worldwide liquid hydrocarbon, natural gas and condensate production include pricing, supply and demand for petroleum products, amount of capital available for exploration and development, occurrence of acquisitions or dispositions of oil and gas properties, regulatory constraints, timing of commencing production from new wells, drilling rig availability, acts of war or terrorist acts and the governmental or military response thereto, and other geological, operating and economic considerations. Some factors that could affect the Phase 2B LPG expansion project include unforeseen problems arising fro m construction and unforeseen hazards such as weather conditions. The foregoing factors (among others) could cause actual results to differ materially from those set forth in the forward-looking statements. The estimated U.K. mark-to-market loss and estimated exploration and administrative expenses are preliminary estimates. All of the forward-looking information is therefore subject to change, and actual results may differ materially from the estimates given in this update. In accordance with the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995, Marathon Oil Corporation has included in its Annual Report on Form 10-K for the year ended December 31, 2003, and subsequent Forms 10-Q and 8-K, cautionary language identifying important factors, though not necessarily all such factors, that could cause future outcomes to differ materially from those set forth in the forward-looking statements.

Media Relations Contacts: Paul Weeditz 713-296-3910

Susan Richardson 713-296-3915

Investor Relations Contacts: Ken Matheny 713-296-4114

Howard Thill 713-296-4140