BACKGROUND:Competency-based models of medical education require reliable and valid assessment of multiple physician roles. AIMS:To develop and evaluate an objective structured clinical examination (OSCE) designed to assess 7 physician competencies (CanMEDS Roles). METHODS:Twenty four candidates from 4 neonatal-perinatal medicine training programs participated in a 10-station OSCE. Ten 5-point rating scales were developed and used to assess the CanMEDS Roles of Medical Expert, Communicator, Collaborator, Manager, Health Advocate, Scholar and Professional. Three descriptors of performance anchored the ratings. For each station, examiners completed appropriate CanMEDS ratings, a station-specific binary checklist and an overall process-related global rating. Trained standardized patients (SP) and standardized health professionals (SHP) completed rating scales that assessed verbal and non-verbal expression, empathy and coherence as well as the overall global rating. RESULTS:Each station incorporated 3-5 physician Roles. Interstation alpha was 0.80 for checklist scores and 0.88 for examiners' overall global rating. Median interstation alpha for individual CanMEDS ratings was 0.72 (range 0.08-0.91). There were significant correlations between examiner Medical Expert scores and SP/SHP overall global scores and between examiner Communicator scores and 4 SP/SHP assessments of communication skills. Second year trainees' CanMEDS scores for each competency were significantly higher than those of first year trainees (p < 0.05). CONCLUSIONS:The OSCE may be useful as a reliable and valid method of simultaneously assessing multiple physician competencies.