The impact of Foucault's work can still be felt across a range of academic disciplines. It is nevertheless important to remember that, for him, theoretical activity was intimately related to the concrete practices of self-transformation; as he acknowledged: `I write in order to change myself.'1 This avowal is especially pertinent when considering Foucault's work on the relationship between sex and power. For Foucault not only theorized about this topic; he was also actively involved in the S&M subculture of the 1970s. Although his explicit discussions of S&M are somewhat piecemeal, in this article I will show how they provide a useful point of access into his broader conception of power relations. Having first reconstructed Foucault's quasi-Sartrean account of creative self-transformation — specifically through one's sexuality — I will then explain why his defence of S&M (as embodying `strategic' power) is insufficiently sensitive to the inherent ambiguities of this `game'.