Over the past 20 years, there has been a growing recognition of the relativity of sexual norms and of the difficulties of exporting Western conceptions of sexuality to different socio-cultural settings. This view has been most clearly articulated in studies of men who have sex with men (MSM) which suggest that the ways in which male-male sexual activity is shaped and constituted vary significantly from place to place. Despite this, 'homosexuality' continues to be treated as an unproblematic category in HIV/AIDS discourse, epidemiological studies of and HIV prevention strategies for MSM in widely different contexts being based on the North American/West European example of gay men. This paper, which draws upon ethnographic research in Madras, highlights important differences between India and the West, not only in the sexual identities and circuits of MSM, but in their sexual partnerships and practices. These differences, it is argued, are not only significant to the epidemiology of HIV transmission, but have important implications for the development and implementation of HIV prevention strategies.