This report addresses the major performance and accountability challenges facing the Department of the Treasury (Treasury) as it seeks to carry out certain aspects of its economic, financial, enforcement, and management missions. It includes a summary of actions that Treasury has taken and that are under way to address these challenges. It also outlines further actions that GAO believes are needed. This analysis should help the new Congress and administration carry out their responsibilities and improve government for the benefit of the American people. This report is part of a special series, first issued in January 1999, entitled the Performance and Accountability Series: Major Management Challenges and Program Risks. In that series, GAO advised the Congress that it planned to reassess the methodologies and criteria used to determine which federal government operations and functions should be highlighted and which should be designated as high risk. GAO completed the assessment, considered comments provided on a publicly available exposure draft, and published its guidance document, Determining Performance and Accountability Challenges and High Risks (GAO-01-159SP), in November 2000. This report addresses the major performance and accountability challenges facing the Department of the Treasury (Treasury) as it seeks to carry out certain aspects of its economic, financial, enforcement, and management missions. It includes a summary of actions that Treasury has taken and that are under way to address these challenges.