The positive rates of hepatitis B surface antigen (HBsAg) and antibody to hepatitis C virus (anti-HCV) were analyzed according to year, sex, age, and serum ALT levels in 1,370 patients with hepatocellular carcinoma (HCC) who visited the Korea Cancer Center Hospital between January 1989 and December 1994. The positive rate of HBsAg was 68.8 to 76.0% per year in patients with HCC, while that of anti-HCV was 3.2 to 9.8% per year. No sex predominance was found in the positive rates of HBsAg and anti-HCV. HBsAg positivity was distributed mostly in the 41 to 50 age group, whereas anti-HCV positivity was distributed mostly in the over 50 age group. Higher positive rate of anti-HCV was observed in HCC patients with serum ALT levels above the normal range than in those with serum ALT levels within the normal range. However, elevated serum ALT levels above the normal range was not related to the positive rate of HBsAg. The relatively low prevalence of anti-HCV in patients with HCC suggests that the role of HCV infection in the development of HCC lower than that of HBV infection in Korea. However, our results suggest that HCV is another potent risk factor for HCC even in HBV endemic areas.