The relationship between sexuality, gay communities and class is potentially a very large problem for AIDS prevention. Class is a historical process which interacts with sexuality in ways still little understood. The complexities of modern class structures need full acknowledgement; labour market groupings are internally divided, and cultural privilege and exclusion are important. A community survey in New South Wales of men who have sex with men shows the class selectiveness usual in such research. An exploration of correlates of labour market position, income and education finds few relationships with attachment to milieu except for involvement with gay organisations, and minor differences in broad measures of sexuality but some class differences in HIV risk-taking and some differences in exposure to information and in attitude. An exploration of several cases from a life-history study of working-class gay men shows the impact of class circumstance on the formation of sexual relationships and points to the accessibility of unlabelled homosexual activity in working-class milieux. Research on working-class education points to the importance of curriculum change in overcoming class exclusion, and is moving towards empowerment models of great relevance in AIDS education.