Patients are uncertain of physicians' quality but learn about the quality of particular physicians through experience in treatment. Patients come to trust physicians who have served them well. This paper explores the economic consequences of patients' learning and trust within a model of the market for physicians' services. In a market equilibrium, there are too many incompetent physicians in practice. Surprisingly, even the more competent physicians have an interest in preventing patients from judging quality except through experience. As we show, all physicians, including the most competent, may oppose steps to inform patients of physicians' quality.