Presently developing attitudes of future physicians towards preventive medicine will likely provide either a major impetus for or barriers to the inclusion of preventive medicine content in medical school curricula and in other formats of physician education. In turn, attitudes about preventive care and its role in medical practice will continue to have a large influence on how much disease prevention and health promotion emphasis physicians provide in their practices. Consequently, it becomes important to study how medical students' attitudes evolve during the process of medical education. Furthermore, to the extent that we can better understand how desired attitudes can be developed and nurtured, the practice of preventive medicine may become more purposeful. Beginning and third-year medical students were surveyed with a 100-item questionnaire designed to assess their attitudes regarding: (a) the relative importance of 20 specific preventive services to the practice of medicine and (b) the adequacy of preclinical coursework for preparing them to offer preventive care in medical practice. The confidence of third year students' in the ability of primary care physicians to provide these specific services was also assessed. Preventive care service areas about which third-year students expressed high confidence in the ability of physicians to provide were: immunizations, health screening physicals, blood pressure control, cancer detection education, family planning, health counseling/education, and sexually transmitted disease prevention. Services that students had low confidence in the ability of physicians to provide were: smoking cessation, nutrition counseling/education and weight reduction. Areas for which little consensus existed regarding the ability of physicians to provide the service were: life style modification, occupational health/safety education, risk factor analysis, genetic counseling and exercise/physical fitness programs. Overall, the results indicated that both entering and third-year medical students have very similar and somewhat positive attitudes about preventive care services in general. Both groups placed a high degree of importance on the same five preventive care services. These were: health counseling/education, smoking cessation, immunization, cancer detection education and blood pressure control. They were, however, somewhat skeptical about the adequacy of present medical education for preparing physicians to provide the services. Such knowledge about the attitudes of students toward preventive care and about effects of curricula on the evolution of these attitudes should assist medical educators as they evaluate and, if necessary, restructure medical education covering preventive care.