Antibodies against hepatitis C virus (anti-HCV) were detected in 60.8% of 78 patients with hepatocellular carcinoma (HCC). Cirrhosis, present in most of the patients, as well as alcohol abuse, age, sex, and alpha-fetoprotein were equally distributed in the anti-HCV-positive and -negative groups. HBsAg positivity was significatively higher in negative anti-HCV group. By contrast, hepatitis B virus (HBV) antibodies were detected more frequently in positive anti-HCV patients than in the negative anti-HCV group. These data must be considered with caution because of the small number of HBsAg-positive patients. It is concluded that the high prevalence of anti-HCV in patients with HCC may suggest an etiological role of the hepatitis C virus, although in relationship to age, alcohol abuse and cirrhosis, the similarity in the two groups questions this hypothesis.