This paper is concerned with the challenges of qualitative research on workplace learning that occurs within co-operative (co-op) education. Co-op education is extensive in Canada, with an estimated 10% of the student population enrolled in co-op secondary education each year. The context for this study was a veterinary clinic in which four co-op students participated. The theoretical framework for the study considered the workplace experiences as curriculum, the special character of experiential learning, and a cognitive perspective on learning from experience. Methodological challenges were evident in four related areas: (1) observation in an unfamiliar setting; (2) goals of the workplace setting; (3) conceptions of knowledge and curriculum; and (4) varieties of learning. The methodological challenges recognized in this study highlight the interplay among the theoretical framework, data collection methods, and data analysis procedures. (Contains 16 references.) (SLD)