BACKGROUND: To examine the long-term effects of hepatitis C virus (HCV) infection in a cohort of patients admitted to Fairfield Hospital with hepatitis from 1971 to 1975. The availability of stored sera from this time enabled testing to identify those who were anti-HCV positive on admission. METHODS: Sixteen per cent (n = 230) of the cohort tested positive for HCV antibody (anti-HCV). The ‘unexposed’ group was selected from those who were anti-HCV negative. Systematic approaches were used to locate the cohort and health outcomes assessed by a study specific questionnaire and clinical review with repeat serology and liver function tests. RESULTS: Complete follow up has been achieved on a subset of 35 HCV-seropositive and 70 seronegative individuals. The seropositive group was significantly more likely to have given a history of injecting drug use, the presumed route of infection. The seropositive group was also more likely to have elevated serum alanine aminotransferase levels, but only two (6%) were known to have progressed to cirrhosis. DISCUSSION: The anti-HCV-positive individuals followed up to date are at increased risk of liver-related pathology, but few had progressed to cirrhotic liver disease. This differs from findings of transfusion-related studies and suggests, within the limitations of the study, that the natural history of community acquired HCV may be more benign.