Over the past 25 years, professionalism has emerged as a substantive and sustained theme, the operationalization and measurement of which has become a major concern for those involved in medical education. However, how to go about establishing the elements that constitute appropriate professionalism in order to assess them is difficult. Using a discourse analysis approach, the International Ottawa Conference Working Group on Professionalism studied some of the dominant notions of professionalism, and in particular the implications for its assessment. The results presented here reveal different ways of thinking about professionalism that can lead towards a multi-dimensional, multi-paradigmatic approach to assessing professionalism at different levels: individual, inter-personal, societal-institutional. Recommendations for research about professionalism assessment are also presented.