Context. - With the public's increasing use of complementary and alternative medicine, medical schools must consider the challenge of educating physicians about these therapies. Objectives. - To document the prevalence; scope, and diversity of medical school education in complementary and alternative therapy topics and to obtain information about the organizational and academic features of these courses. Design. - Mail survey and follow-up letter and telephone survey conducted in 1997-1998. Participants. - Academic or curriculum deans and faculty at each of the 125 US medical schools. Main Outcome Measures. - Courses taught at US medical schools and administrative and educational characteristics of these courses. Results. - Replies were received from 117 (94%) of the 125 US medical schools. Of schools that replied, 75 (64%) reported offering elective courses in complementary or alternative medicine or including these topics in required courses. Of the 123 courses reported, 84 (68%) were stand-alone electives, 38 (31%) were part of required courses, and one (1%) was part of an elective. Thirty-eight courses (31%) were offered by departments of family practice and 14 (11%) by departments of medicine or internal medicine. Educational formats included lectures, practitioner lecture and/or demonstration, and patient presentations. Common topics included chiropractic, acupuncture, homeopathy, herbal therapies, and mind-body techniques: Conclusions. - There is tremendous heterogeneity and diversity in content, format, and requirements among courses in complementary and alternative medicine at US medical schools.