<p>Abstract</p> <p>Background</p> <p>As the overall evidence for the effectiveness of teaching of evidence based medicine (EBM) is not strong, and the impact of cultural and societal influences on teaching method is poorly understood, we undertook a randomised-controlled trial to test the effectiveness and learning satisfaction with two different EBM teaching methods (usual teaching vs. problem based learning (PBL)) for undergraduate medical students.</p> <p>Methods</p> <p>A mixed methods study that included a randomised-controlled crossover trial with two intervention arms (usual teaching and PBL) and a nested qualitative study with focus groups to explore student perceptions of learning and to assess the effectiveness and utility of the two teaching methods.</p> <p>All 129 second-year medical students at the University of Hong Kong in 2007.</p> <p>The main outcomes measures were attitudes towards EBM; personal application and current use of EBM; EBM knowledge; future use of EBM.</p> <p>Results</p> <p>PBL was less effective at imparting knowledge than usual teaching consisting of a lecture followed by a group tutorial. After usual teaching students showed improvement in scores for 'attitudes towards EBM', 'personal application and current use of EBM' and 'EBM knowledge, which were not evident after PBL. In contrast to the usual teaching, students found PBL difficult as they lacked the statistical knowledge necessary to support discussion, failed to understand core concepts, and lost direction.</p> <p>Conclusion</p> <p>The evidence presented here would suggest that the teaching of EBM within an Asian environment should adopt a format that facilitates both the acquisition of knowledge and encourages enquiry.</p>