This study investigates fourth-year pharmacy students' experiences of problem-based learning (PBL). It adopts a phenomenographic approach to the evaluation of problem-based learning, to shed light on the ways in which different groups of students conceive of, and approach, PBL. The study focuses on the way students approach solving problem scenarios in class, and using professional pharmacy databases on-line. Qualitative variations in student approaches to solving problem scenarios in both learning situations are identified. These turn out to be associated with qualitatively different conceptions of PBL and also with levels of achievement. Conceptions and approaches that emphasis learning for understanding correlate with attaining higher course marks. The outcomes of the study reinforce arguments that we need to know more about how students interpret the requirements of study in a PBL context if we are to unravel the complex web of influences upon study activities, academic achievement and longer-term professional competence. Such knowledge is crucial to any theoretical model of PBL and has direct practical implications for the design of learning tasks and the induction of students into a PBL environment.