The U.S. health system has been described as the most competitive, heterogeneous, inefficient, fragmented, and advanced system of care in the world. In this paper, we consider two questions: First, is the U.S. healthcare system productively efficient relative to other wealthy countries, in the sense of producing better health for a given bundle of hospital beds, physicians, nurses, and other factor inputs? Second, is the United States allocatively efficient relative to other countries, in the sense of providing highly valued care to consumers? For both questions, the answer is most likely no. Although no country can claim to have eliminated inefficiency, the United States has high administrative costs, fragmented care, and stands out with regard to heterogeneity in treatment because of race, income, and geography. The U.S. healthcare system is also more likely to pay for diagnostic tests, treatments, and other forms of care before effectiveness is established and with little consideration of the value they provide. A number of proposed reforms that are designed to ameliorate shortcomings of the U.S. healthcare system, such as quality improvement initiatives and coverage expansions, are unlikely by themselves to reduce expenditures. Addressing allocative inefficiency is a far more difficult task but central to controlling costs.