Problem-based learning (PBL) is now used at many medical schools to promote lifelong learning, open inquiry, teamwork, and critical thinking. PBL has not been compared with other forms of discussion-based small-group learning. Case-based learning (CBL) uses a guided inquiry method and provides more structure during small-group sessions. In this study, we compared faculty and medical students' perceptions of traditional PBL with CBL after a curricular shift at two institutions.