Little research exists regarding men who have sex with men and sexual risk in Nigeria. Prior to the implementation of a targeted HIV/STI prevalence study, structured focus groups incorporating anonymous questionnaires were conducted with members of this population in secure locations in Nigeria. A purposive sample of men was recruited by word-of-mouth. Five focus groups were conducted with a total of 58 men. Mean age was 27 years (range 16-58); 60% had post-secondary education; 56% were employed full or part-time; 83% were Christian; 16% were Muslim; 66% self-identified as bisexual; 31% as homosexual. Participants' experiences were diverse, with ethnic, religious and class distinctions strongly structuring sexual expression. Same-sex community networks were hidden, with social activities taking place in non-commercial, private venues. Socially ostracized by culture, religion, and political will, the risks embodied within same-sex activity are high. For Nigeria — a nation culturally rich and religiously devout — the implications for public health policy are complex. However, these research findings suggest that immediate action is vital to mitigate the impacts of HIV and other STIs.