The incidence of hepatocellular carcinoma (HCC) in Japan has been increasing. The aim of the present study was to analyze epidemiological changes in Japanese HCC patients. A total of 463 patients with HCC diagnosed at our hospital between 1982 and 2001 were recruited for this study. Cohorts of patients with HCC were categorized into intervals of five years. The number of HBV- and HCV-associated HCC cases had decreased and increased in 1987-1991, respectively, and thereafter reached a plateau. The mean age of patients at diagnosis of HCV-associated HCC showed a steady significant increase from 60 to 68 years of age during the period, suggesting that these findings were associated with a shift toward an older-age group that had the highest rate of HCV infection. The mean age of patients with other types of HCC did not significantly change during the period. Since it is known that the prevalence of HCV infection in young Japanese persons is low and that the incidence of HCV infection is very low at present, our findings may indicate that the prevalence of HCC will decline in Japan, an advanced country with regard to HCV-associated HCC, in the near future.