Objective: To explore the experience and practice of students entering a problem-based (PBL) medical undergraduate course and to identify contributory social, curricular and contextual factors. Design: A multiple case study exploiting the natural experimental features of the setting. Qualitative data collection methods, including participant observation, interviews and focus groups were supplemented by a survey. Setting: The medical school at the University of Liverpool between 1996 and 1998, which launched an integrated PBL curriculum inline with recommendations of the General Medical Council of the UK. Participants: Two successive cohorts of first year medical students entering the PBL course. Results: The first case study findings demonstrated student insecurity and dependence on the faculty resources rather than conforming to PBL principles. Uncertainty gradually diminished but resource dependence persisted, endorsed by peer interaction. Survey results confirmed the qualitative findings. The hypotheses raised for the second case study predicted replications of resource dependent learning, social influences and initial insecurity. Only the first two were upheld. Second year students' advice on textbooks undercut initial uncertainty but insecurity and social comparison reappeared following the changeover of PBL groups and tutors in the second semester. Survey results were replicated. Conclusion: Student learning was socially agreed amongst the peer group and directed by faculty given resources. It was not self-directed. Claims made for PBL type curricula may not be justified and GMC recommendations may remain unfulfilled without rigorous attention to educational principles.