OBJECTIVES: This study examined an outbreak of hepatitis A in eastern Sydney during 1991-1992. METHODS: Data were based on cases of hepatitis A in eastern Sydney residents reported from January 1991 to October 1992. RESULTS: Five hundred seventy cases of hepatitis A were reported. Of these, 515 (90%) occurred in male patients, of whom 330 were reported to be homosexual or bisexual. The highest attack rate (71/10,000) occurred in men aged 20 to 29 years of age. CONCLUSIONS: This outbreak affected large numbers of young homosexual men living in the inner eastern suburbs of Sydney. Hepatitis A vaccination should be considered for all susceptible homosexual men. Further research into the use of hepatitis A vaccine as an outbreak control measure is also recommended.