This study was designed to evaluate the effects of a required ambulatory care clerkship during the fourth year of medical school on the students' knowledge of primary care medicine and their subsequent career choices. A questionnaire was mailed to the graduates of the Albert Einstein College of Medicine classes of 1985-1989. Fifty-six percent (408) of the questionnaires were returned. An average of 74% of the respondents answered yes to six items that asked whether the clerkship had successfully introduced them to basic concepts and practices of outpatient medicine (range from 58% to 93%, depending on the item). In addition, 90% reported that the clerkship had enhanced their understanding of primary care medicine, while 41% indicated that the rotation had wholly or partially influenced their career choices. The survey findings suggest that exposure to outpatient medicine during medical school plays an important role in facilitating students' knowledge of primary care medicine and influencing their career choices.