BACKGROUND: Gay men who request nonoccupational postexposure prophylaxis (PEP) may seek preexposure prophylaxis (PrEP) should this become available. We explored trends and predictors of PEP use among Australian gay men to inform future biomedical prevention programs. METHODS: We used 2001-2010 data from Gay Community Periodic Surveys in 3 Eastern Australian states and assessed PEP awareness and use in the 6 months before each survey, and among HIV-uninfected men in all surveys predictors of PEP use. Analytical methods included chi-square test for trend and multivariate log-binomial estimation of associations. RESULTS: The awareness of PEP significantly increased from 23% in 2001 to 64% in 2010. PEP use also increased from 2.3% to 3.9%, respectively. PEP use was significantly associated with being in a regular relationship with an HIV-serodiscordant partner, higher number of sex partners, engaging in anal intercourse with casual partners, and regularly testing for HIV/sexually transmitted infections. However, fewer than 8% of men who engaged in these practices reported PEP use. CONCLUSIONS: Our findings highlight the profiles of current PEP users: men in HIV-serodiscordant relationships, and men having high numbers of casual partners and unprotected anal intercourse with them. These men are in need of effective HIV prevention strategies and may be receptive to preexposure prophylaxis in the future. Presently, targeted HIV education to improve risk assessment skills may prevent some seroconversions through the appropriate use of PEP.