This study investigated changes, over a one-year period, in medical and dental students' attitudes toward various issues related to contact with AIDS patients. In 1988 and 1989, the authors surveyed second- and third-year medical and dental students at one medical school both before and after they completed a year of required clinical training. The dental students remained consistently more anxious and more restrictive in their attitudes toward treating patients with AIDS than did their medical student counterparts, and became more conservative (fearful) in their attitudes after working with AIDS patients, whereas the medical students became more liberal. Overall, both groups were more concerned about contracting AIDS in their professional lives than in their personal lives. Over one-third of the medical students and two-thirds of the dental students indicated that they did not wish to train in a specialty or hospital with a high percentage of AIDS patients, and a substantial minority of the students in both groups did not feel that they were responsible for treating all patients whom they were qualified to treat. These and related results suggest that AIDS-related anxiety may influence students' career choices and behaviors and the quality of care patients receive. Suggestions for educational strategies to address students' fears--both warranted and unwarranted--and the differences in attitudes between students of different health-care professions are discussed.