Cheating among students is surprisingly frequent and may be increasing. The 1991 study reported herein was prompted by an episode of cheating involving three second-year medical students at the University of New Mexico School of Medicine (UNM SOM) and was undertaken (1) to elicit the opinions of faculty members and students at that institution about whether selected descriptions of students' behaviors were unethical; (2) to document possible discrepancies between the opinions of the two groups concerning these behaviors; (3) to define the prevalence of unethical behavior among current students as estimated by faculty and students; and (4) to determine how best to approach future instances of unethical behavior. Questionnaires were distributed to all faculty and students. The first two parts, sent to both groups, concerned reactions to a series of described physician and student behaviors. For each described behavior, respondents were asked whether or not it was unethical and, for the described student behaviors, whether they had personal knowledge of such behavior by local medical students. The third portion of the questionnaire concerned faculty perceptions regarding students' behaviors over time. With the exception of the class involved in the cheating incident, faculty and students were surprisingly similar in their opinions regarding the ethical nature of the described behaviors. According to both faculty and students, there was a significant incidence ( > or = to 10% of the respondents) of unethical behavior at the school of medicine, most commonly in relation to cheating on examinations.(ABSTRACT TRUNCATED AT 250 WORDS)