The purpose of this study was to clarify the clinicopathologic differences of hepatocellular carcinoma associated with the hepatitis B versus the hepatitis C virus. One hundred and sixty-eight patients with resected hepatocellular carcinoma were tested for viral hepatitis. Ten (6%) had both the hepatitis B surface antigen and antibodies to the hepatitis C virus. Thirty-three (20%) had neither marker. Sixteen (9%) had only the hepatitis B surface antigen (group B), and 109 (65%) had only antibodies to the hepatitis C virus (group C). We compared groups B and C clinicopathologically. The mean tumor diameter was larger in group B than in group C (6.3 cm vs 3.4 cm), while group B patients were younger than group C (48 yrs vs 62 yrs, p<0.0001). Poor liver function, histologic cirrhosis and chronic active hepatitis were frequently found in group C. The 1- and 2-year tumor-free survival rates following surgery in group B were 67% and 33%, and those in group C were 73% and 49%. The 1-, 2-, and 3-year survival rates following surgery in group B were 78%, 68%, and 0%, while those in group C were 92%, 83%, and 76% (p=0.0189). Hepatocellular carcinoma with concomitant hepatitis B viral infection was found to present as larger tumors in younger patients with less severe liver dysfunction. Hepatocellular carcinoma with concomitant hepatitis C viral infection was often detected in follow-up studies when it was small.