This study represents an effort to refine our understanding of measurement of professional self-concept by testing a tool across various strata of nursing students. The Professional Self Concept of Nurses Instrument, developed in studies of Australian nursing students, was applied to samples of basic undergraduate, post-basic and graduate students in a Canadian university nursing programme. The findings suggest that the tool is sensitive to the predictable development of professional self-concept as students advance through professional education, especially in the dimensions of professional practice and satisfaction. The authors propose that the instrument may have specific applications in evaluating the effects of traditional and innovative educational strategies upon the evolution of professional self-concept in nurses.