Sports Medicine as an apparent sub-class of medicine has developed apace over the past 30 years. Its recent trajectory has been evidenced by the emergence of specialist international research journals, standard texts, annual conferences, academic appointments and postgraduate courses. Although this field of enquiry and practice lays claim to the title 'sports medicine' this paper queries the legitimacy of that claim. Depending upon how 'sports medicine' and 'medicine' are defined, a plausible-sounding case can be made to show that sports medicine is not in fact a branch of medicine. Rather, it is sometimes closer to practices such as non-therapeutic cosmetic surgery. The argument of the paper is as follows. It begins with a brief statement concerning methodology. We then identify and subscribe to a plausible defining goal of medicine taken from a recognised authority in the field. Then two representative, authoritative, definitions of sports medicine are discussed. It is then shown that acceptance of these definitions of sports medicine generates a problem in that if they are accepted, no necessary commitment to the defining goal of medicine is present within sports medicine. It seems to follow that sports medicine is not medicine. In the final part of the paper a critical response to that conclusion is presented and rebutted. The response is one which rejects the identification of the defining goal of medicine upon which our argument rests.