Objectives To examine aggregate changes in homosexual HIV risk-taking among gay men attending the Gay Pride festival in the United Kingdom over a 3-year period during which HIV prevention activity targeted at this population increased considerably. Design Three cross-sectional self-completion questionnaires at yearly intervals asking identical questions on sexual behaviour in the preceding year. Setting Lesbian and Gay Pride festival held in London, June 1993, 1994 and 1995. Participants Men attending the festival who were UK resident, had ever had sex with another man and who were willing to fill out a questionnaire (n = 1620, 1753 and 1168 in 1993, 1994 and 1995, respectively). Main outcome measures Self-reported numbers of sexual partners, sexual partners with whom anopenile intercourse occurred and sexual partners with whom anopenile intercourse occurred without a condom. Results Over the 3-year period there were no changes in the proportion of men engaging in any of the sexual behaviour measures. At each cross-section, one in three men (514 out of 1566, 511 out of 1612, 351 out of 1059 in 1993, 1994 and 1995, respectively) had engaged in anopenile intercourse without a condom with at least one male partner in the preceding year and one in 10 (162 out of 1566, 156 out of 1612, 103 out of 1059 in 1993, 1994 and 1995, respectively) had done so with more than one male partner. Conclusion Despite an increase in prevention work targeted at this population, aggregate levels of sexual risk-taking have remained very stable. A reassessment of the efficacy of current HIV prevention messages and methods with this population is urgently required.