Thirteen of 81 patients with chronic hepatitis and positive hepatitis C virus (HCV) antibody developed hepatocellular carcinoma (HCC) during a follow-up period of 54 +/- 38 months. The histopathological findings in HCC-bearing liver in these patients included six cases of chronic persistent hepatitis [CPH; mean hepatitis activity index (HAI) score: 5.8] and seven cases of chronic aggressive hepatitis (CAH) 2A, or 2B (HAI) score: 13.6). Multiple biopsies of the liver in six cases revealed that five cases, including four with CPH at the time of HCC diagnosis, previously had histopathological findings identical to CAH 2A, and another case constantly had CPH during the 8-year follow-up. These findings suggest that HCV-associated HCC can occur even in patients with HCV antibody positivity and inactive or mild chronic hepatitis. This is of interest in the pathogenetic mechanisms of HCV-associated HCC.