The Centers for Medicare and Medicaid Services (CMS) annually publishes two measures of Medicare's administrative expenditures. One of these appears in the reports of the Medicare Boards of Trustees and the other in the National Health Expenditure Accounts (NHEA). The latest trustees' report indicates Medicare's administrative expenditures are 1 percent of total Medicare spending, while the latest NHEA indicates the figure is 6 percent. The debate about Medicare's administrative expenditures, which emerged several years ago, reflects widespread confusion about these data. Critics of Medicare argue that the official reports on Medicare's overhead ignore or hide numerous types of administrative spending, such as the cost of collecting taxes and Part B premiums. Defenders of Medicare claim the official statistics are accurate. But participants on both sides of this debate fail to cite the official documents and do not analyze CMS's methodology. This article examines the controversy over the methodology CMS uses to calculate the trustees' and NHEA's measures and the sources of confusion and ignorance about them. It concludes with a discussion of how the two measures should be used.