Our vision is to be recognized as the pacesetter in creating superior value growth through innovative energy solutions and unique partnerships.           Marathon Oil Corporation Marathon (NYSE:MRO) is an integrated international energy business engaged in exploration, development, production, refining, marketing and transportation. Headquartered in Houston, Texas, Marathon has oil and gas activities in the United States, the United Kingdom, Angola, Canada, Equatorial Guinea, Gabon, Ireland, Norway and Russia. Marathon is a leading refiner and marketer in the United States through our 62 percent interest in Marathon Ashland Petroleum LLC (MAP). Contents Financial Highlights Letter to Shareholders Focusing and executing on the strategies that deliver value Exploration success Rebalanced program leads to nine discoveries in 2003 New upstream core areas Investment and growth continue in Equatorial Guinea, Norway and Russia Integrated gas Linking stranded supply with key demand areas Strong downstream performance MAP income more than doubles 2002 level Financial flexibility Asset rationalization program generates more than $1.2 billion Operational Review 2003 was a strong year for Marathon Corporate Responsibility Marathon is committed to good corporate citizenship Corporate Officers Board of Directors Corporate Information   Above: Marathon's 2003 return to Russia through an acquisition in Western Siberia represents resource potential of more than 900 million barrels of oil. The acquisition includes three producing fields along the Left Bank of the Ob River with more than 250 million barrels of proved and probable reserves and six operated, undeveloped fields on the Right Bank that are under appraisal.