Much research has concluded that young gay men are at disproportionately higher risk of HIV infection through unsafe sexual behaviour. This paper is the first report on this particular group in the UK. As part of a larger cohort study, 111 young (less than 21) gay and bisexual men were interviewed about their sexual behaviour, knowledge of AIDS and HIV, particularly safer sexual practices and other factors. Three per cent had not had sex and 13% had not had anal intercourse with a man at the time of interview. Forty-five per cent had sexual experience with a woman and 34% had engaged in vaginal intercourse. The average age at first homosexual experience was just under 15 years and this is higher than other age groups in the cohort. Median number of male partners in the year before interview was 5, with 1 of whom anal intercourse occurred. Sexual repertoire was relatively restricted compared to older men. Condom use was slightly more consistent and levels of knowledge not significantly different. From these findings, the contention that young gay men are at higher risk of HIV infection through risky sexual behaviour is not supported.