We evaluated the beliefs of second-year medical students regarding critical issues in the AIDS epidemic before and after an intensive two-day training symposium. Paired responses, collected for three consecutive years, were available for 187 students. Our results indicate that, although the students generally held progressive beliefs on prevention and public policy prior to training, a significant minority held views that differ from expert opinion. After the training experience, we observed substantial shifts of opinion on several issues. For example, among those who initially believed that physicians should record results of HIV testing in patient charts without patient permission, 45% shifted to disagreement. On mandatory premarital testing, 43% of those initially supporting it shifted to disagreement. On some issues, such as contact tracing, where expert opinion is less clear, student opinion moved very little overall. Over the three-year period, we found evidence of a trend towards less concern over HIV transmission to men from causal sex with infected female partners and a trend towards acceptance of glove-wearing when handling all blood specimens. In conclusion, we demonstrate that the beliefs of medical students concerning difficult issues posed by the AIDS epidemic can be changed substantially in the short-term by a specially designed intensive educational program. Reinforcement and persistence of these changes should now be a concern for medical educators.