OBJECTIVE: This study examines medical students' attitudes towards peer accountability. METHODS: A nationally representative sample of 564 third year medical students was surveyed. Students reported their agreement or disagreement with two statements: "I feel professionally obligated to report peers whose personal behaviors compromise their professional responsibilities" and "I feel professionally obligated to report peers who I believe are seriously unfit to practice medicine." RESULTS: The majority of students (81.6 %) either agreed strongly or agreed somewhat that they feel obligated to report peers whose personal behaviors compromise their professional responsibilities. The majority (84.1 %) also agreed that they feel professionally obligated to report peers who they believe are seriously unfit to practice medicine. CONCLUSION: In contrast with previous studies, this national study found that a significant majority of students reported that they feel obligated to report unfit peers.