OBJECTIVE: To determine the prevalence and risk factors for hepatitis C (HCV) in HIV-negative homosexual men in Sydney. METHODS: A cohort study was conducted in a sample of community-based, HIV-negative, homosexual men in Sydney. Participants underwent a face-to-face interview regarding sexual behaviour, sexually transmissible infections, and injecting drug use (IDU). RESULTS: Eight hundred and twenty-four men consented to HCV testing, and the prevalence was 0.85% (95% CI 0.34-1.74). HCV seropositivity was strongly associated with a history of IDU (OR = 60.43, 95% CI 6.70-544.79). All HCV seropositive individuals reported a history of either IDU or other means by which they may have had parenteral exposure to HCV. There was no evidence of an independent association between sexual behaviour and HCV infection. CONCLUSION: The prevalence of HCV in this cohort was about the same as in the general population in Australia, and there was no evidence for sexual transmission in this population.