OBJECTIVES: The aim of the study was to explore the awareness of rectal microbicides, the use of pre-exposure prophylaxis (PREP) and the willingness to participate in biomedical HIV prevention trials in a cohort of HIV-negative gay men. METHODS: In a community-based cohort study, HIV-negative homosexually active men in Sydney, Australia were questioned about awareness of rectal microbicides, use of PREP, and willingness to participate in trials of such products. Predictors of awareness and willingness to participate were analysed by logistic regression. Use of PREP was examined prospectively. RESULTS: Overall, 14% had heard of rectal microbicides. Older (P=0.05) and university-educated men (P=0.001) were more likely to have knowledge of rectal microbicides. Almost one-quarter (24%) of men reported that they were likely/very likely to participate in rectal microbicide trials. Among those men with definite opinions on participation, awareness of rectal microbicides was significantly associated with unwillingness to participate [odds ratio (OR) 0.78, 95% confidence interval (CI) 0.65-0.93, P=0.007]. Willingness to participate in trials using antiretroviral drugs (ARVs) to prevent HIV infection was reported by 43% of men, and was higher among those who reported unprotected anal intercourse (UAI) with HIV-positive partners (OR 1.88, 95% CI 0.99-3.56). There was no evidence of current PREP use. CONCLUSIONS: This study demonstrates that Australian gay men have had little experience with PREP use and rectal microbicides. About half would be willing to consider participation in trials using ARVs to prevent HIV infection. Extensive community education and consultation would be required before PREP or rectal microbicides could be trialled in populations of gay Australian men.