Physiology is an integral component of any medical curriculum. Traditionally, the learning of physiology has relied heavily on systems-based didactic lectures. In 2001, the Nelson R. Mandela School of Medicine (NRMSM; Durban, South Africa) embarked on a problem-based curriculum in which the learning of physiology was integrated with relevant clinical scenarios. Students are expected to gain an understanding of physiology through self-directed research with only certain aspects being covered in large-group resource sessions (LGRSs). It has gradually become evident that this approach has resulted in significant gaps in students' understanding of basic physiological concepts. A survey of student perceptions of needs for physiology was undertaken to gain a better understanding of their perceived problems and also to inform them of proposed curricular changes. Students were asked to what extent they thought physiology was essential for their understanding of pathology, interpretation of patients' clinical signs and presentation of symptoms, and analysis of laboratory results. Students were also invited to detail the difficulties they experienced in understanding in LGRSs on clinical and physiological topics. The results of the survey indicate that greater interaction of students with experts is needed. In particular, students felt that they lacked the basic conceptual foundations essential for the learning and understanding of physiology, since the difficulties that the students identified are mainly terminological and conceptual in nature. (Contains 6 tables and 1 footnote.)