In the sociological literature, medicalization is often theorized as a depoliticizing force. This perspective plays a central role in longstanding debates in gender studies over whether transgender subjectivities challenge or reinforce binary constructs of sex and gender. However, if medicalization is inherently depoliticizing, how do we explain the shift—in a matter of mere decades—from transsexualism as a nascent medical diagnosis to a highly articulated transgender identity and struggle for transgender rights in a host of social and cultural arenas? This dissertation explores this question by examining the evolution of and relationship between medicine and the transgender rights movement. Borrowing from institutional ethnography, I employ a triangulated methodological approach that includes: in-depth interviews with activists and health care providers; participant observation at transgender health conferences and community events; and discourse analysis of historical and contemporary materials on transgender medicine and health. Findings reveal that the material and discursive practices of medicine not only shape transgender people's experiences in health care settings but also influence how we define (trans)gendered subjectivity, thus shaping the contours of (trans)gender identity and rights in a variety of social institutions, and in culture at large. The multiple, and often contradictory, functions and effects of medicalization result in a tension between resistance to and reliance on medicine within the transgender rights movement. For instance, constructions of transgender identities as pathological are rejected at the same time as bio-medical models are accepted or advocated as a means to gain rights and recognition. Health care providers are also conflicted about medicalization, which leads them to variously adopt, resist, and reframe the official discourses and protocols of their professions in their day-to-day work. I use these findings to theorize medicalization as a site of struggle rather than a static variable, and forward an account of the transgender rights movement as an embodied health movement. While transgender subjects and subjectivities have typically not been considered outside of gender studies, this research demonstrates how attention to transgender medicine and movements can also contribute to the literature in both medical sociology and social movements.