To clarify the role of the hepatitis B virus (HBV) in hepatocellular carcinoma (HCC) associated with alcohol consumption, HBV-DNA in the liver of 19 patients with HCC were investigated. HBV-DNA was examined by Southern blot hybridization. HBV-DNA was integrated into tumor cells from five out of six (83%) patients with HCC associated with HBs antigen (HBsAg)-positive post-hepatitic liver cirrhosis (LC), but this was not related to the history of alcohol intake. In 13 HCC patients of HBsAg-negative alcoholic LC, HBV-DNA integration was not detected in any patient. These findings suggest that HBV does not play a major role in the pathogenesis of HCC in HBsAg-negative alcoholics in Japan.