OBJECTIVE To improve medical students' ability and willingness to obtain occupational histories from their patients. METHODS General medicine faculty and internal medicine teaching residents, who participated as instructors, and medical students during their required internal medicine clerkships. METHODS The primary teaching hospitals of two medical schools. METHODS During alternate months, students participated in problem-based sessions that included occupational health objectives (intervention) or attended the standard small-group didactic sessions (control). Process evaluations were collected from students and faculty in the intervention group following each session. Outcome evaluation was performed using chart audit and multiple-choice testing to compare the intervention and control groups. METHODS Intervention students participated in at least one problem-based session incorporating occupational aspects of disease into clinical internal medicine. Instructors received information packets and materials but had no other expertise in occupational medicine. RESULTS The great majority of ratings on the process evaluations showed that the students were "moderately" to "extremely" interested in the session attended. No student rated any session to be a "waste of time," and over 90% of students would recommend the session being evaluated to a friend. Chart audit showed that students in the intervention group recorded slightly more occupational information than did those in the control group (an average of 2.97 vs. 2.37 pieces of information, p = 0.06). When the most commonly documented data (employment status and job title) were ignored, the difference between group means (1.1 vs. 0.91) was significant (p = 0.03), suggesting that intervention students were more likely to probe further into a patient's occupational history. Both groups of students collected less occupational information from women than from men (t = 3.22, p = 0.0035). Multiple-choice tests revealed no difference between the two groups in overall medical knowledge or occupational medicine knowledge. CONCLUSIONS Problem-based learning with specific occupational content is well accepted by students and modestly improves their occupational history taking.