To provide the best care to patients, a physician must commit to lifelong learning, but continuing education and evaluation systems in the United States typically require little more than records of attendance for professional association memberships, hospital staff privileges, or reregistration of a medical license. While 61 of 68 medical and osteopathic licensing boards mandate that physicians participate in certain numbers of hours of continuing medical education (CME), 17 of them require physicians to participate in legislatively mandated topics that may have little to do with the types of patients seen by the applicant physician. Required CME should evolve from counting hours of CME participation to recognizing physician achievement in knowledge, competence, and performance. State medical boards should require valid and reliable assessment of physicians' learning needs and collaborate with physician and CME communities to assure that legislatively mandated CME achieves maximal benefit for physicians and patients. To assure the discovery and use of best practices for continuing professional development and for maintenance of competence, research in CME and physician assessment should be raised as a national priority. (Contains 1 table.)