Aim: To assess the influence of a graduate-entry PBL (problem-based learning) curriculum on individual learning style; and to investigate the relationship between learning style, academic achievement and clinical reasoning skill. Method: Subjects were first-year medical students completed the Study Process Questionnaire at the commencement, and again, at the end of the academic year when they also completed the Diagnostic Thinking Inventory (DTI), a measure of clinical reasoning skill. Subjects were classified on the basis of their predominant learning approach, and this was correlated with examination results and DTI score. Results: There was a net shift in predominant learning approach away from deep learning towards a more surface approach over the period of the study, as well as a significant decrease in deep-learning scores. There was a statistically significant association between deep learning score and clinical reasoning skill as shown by total DTI score as well as on the structure of knowledge subscale. No correlation was found between learning approach and examination results. Conclusion: Although these results suggest that a deep learning approach may be beneficial in the development of clinical reasoning skill through its potential to enhance the development of knowledge representations, the substantial shift towards a surface learning approach brings into question previous conclusions that PBL curricula foster a deep approach to learning, and suggests that other factors, such as work load may be more determinants of learning approach than curriculum type. Taken together, these findings emphasise the context-dependent nature of learning approach as well as the importance of assessment as a driver of student learning and strongly suggest that further work to determine precisely the factors which influence learning approach in medical students is urgently needed.