Characteristics of 205 consecutive patients with hepatocellular carcinoma (HCC) admitted during 1990 to 1993 have been analyzed from the standpoint of hepatitis viral infection in Japan. Among 205 HCC patients, 71% of the patients showed positivity for hepatic C virus (HCV) antibody alone, 13% showed positivity both for HCV and HBV (HCV/HBV) antibody, 11% demonstrated HBsAg alone, and negativity of both HCV and HBV antibody in 4% only. Positivity to both HCV antibody and HBsAg was demonstrated in 1% only. Mean detection age of HCVAb-positive HCC as well as both HCV/HBV antibody-positive HCC was 62 ± 7 years, in contrast to 52 ± 13 years in HCC with HBsAg (P < .05). Male-to-female ratio among HCVAb-positive HCC was 3.3:1, in contrast to 5.5:1 among the HCV/HBVAb-positive HCC and 7:1 among HBsAg-positive HCC, but there was no significant difference in the gender distribution between these groups. More than 60% of HCVAb-positive HCC were classified into the stage of Child B and C, whereas 65% of HBsAg-positive HCC was at the stage of Child A. The severity of liver disease was confirmed by liver histology, indicating that more than 70% of the HCVAb-positive HCC and the HCV/HBVAb-positive HCC showed cirrhosis, in contrast to 50% among the HBsAg-positive HCC. Three-year survival rate of HCV Ab-positive HCC and HBV/HCVAb-positive HCC was 68% and 56%, respectively, in contrast to 47% in HBsAg-positive HCC. HCC was found at early stage among the patients receiving periodic medical checkups beforehand, and the prognosis of these HCC patients was significantly better than those who did not receive checkups. From these results, HCV-related HCC occupied over 80% of total HCC in Japan, which are characterized by older age and more severe cirrhosis, as compared with HBsAg-positive HCC. Prognosis of HCV Ab-positive HCC was not significantly better than HBsAg-positive HCC, but the periodical screening naturally improves prognosis because the cases are found usually much earlier (lead time bias) and mostly belong to slow progression type (length bias). (HEPATOLOGY 1995; 22:1027–1033.).