The purpose of this study was to understand how men and women define sexual desire and sexual arousal and how they distinguish between the two. The authors conducted 32 semi-structured interviews with individuals in South East England, using a purposive sampling strategy to maximize the variation in experience of sexual function across the group. The authors identified three criteria that participants used to define and distinguish between desire and arousal: the sequence in which they occurred; whether the mind or the body (or both) were engaged; and the extent to which feelings of desire or arousal were responsive (in response to person or stimulus) and motivational (oriented toward a goal). Most participants attempted to distinguish between desire and arousal when prompted, but often with difficulty. Participants commonly felt that desire preceded arousal; some felt that desire was "mind" and arousal "body"; and many felt that both desire and arousal were responsive and motivational. However, the authors identified numerous times when these distinctions were reversed or the differences between terms were blurred. The results support recent proposals to merge the two diagnostic categories of female sexual arousal disorder and hyposexual desire disorder into a single diagnostic category.