The political legitimacy and policymaking influence of the medical profession have greatly declined in American society over the past 30 years. Despite speculation about the causes, there has been little empirical research assessing the different explanations. To address this gap, data collected in 1995 are used to compare attitudes of the American public and policy elites toward medical authority. Statistical analyses reveal that (1) elites are more hostile to professional authority than is the public; (2) the sources of declining legitimacy are different for the public than they are for policy elites; and (3) the perceptions that most threaten the legitimacy of the medical profession pertain to doubts about professional competence, physicians' perceived lack of altruism, and limited confidence in the profession's political influence. This article concludes with some speculations about the future of professional authority in American medicine.