Background : To implement effective behaviour change interventions for men who have sex with men, qualitative information was collected about the contexts and meanings of sex and relationships between men in Ho Chi Minh City. Methods: Individual interviews and focus groups were conducted with 74 men aged 18 years or older who had had sex with another man in the previous 12 months. Results: Findings reveal that sex between men exists and is associated with two common descriptors in Vietnam: bong lo for those who are feminised in public and bong kin for those who are not, and are often married. In sexual relationships, for both groups of men, there is a trade off between sexual pleasure and risk. Condoms may not be used, particularly when having sex with a partner who was considered to be good looking or perceived as ‘clean’. Conclusions: The study highlights the need for HIV prevention programs which address issues of sexual meaning in male-to-male sexual relationships.