Formal audits of the continuing medical education activities of physicians licensed in Michigan were undertaken to assess compliance with a law mandating participation in 150 hours of continuing medical education each 3 years. A random sample of all physicians renewing their licenses in 1987 and 1988 were asked to provide documentation of their continuing medical education activities. The average physician participated in 175 hours of category I approved activities; 53.1% of the hours were obtained in a different state, and only 27.6% were obtained in the home community. A total of 13.7% (132/967) of the physicians were initially unable to document 150 hours of credit. Documentation deficiencies and addition errors were found on 72.5% of forms. If formal audits of compliance with legislation are to be undertaken, early notification of the participants and specific instructions for compliance are needed. Because of problems with documentation, only category I approved activities, with exclusions for trainees, should be used to assess compliance.