Blood specimens from 210 leprosy patients (average age 67.4 years old) and 84 staff members (average age 43.5 years old) in National Leprosarium Suruga were tested for anti-HCV antibody using Ortho's Ab ELISA system. Among the patients, 17 patients had chronic hepatic dysfunction as well as leprosy. Twenty of the 210 patients (9.5%) had anti-HCV antibody in their blood. Eleven of the 17 patients (65%) with chronic hepatic dysfunction were positive for anti-HCV antibody. Only one of the staff member was anti-HCV antibody positive. This high positive ratio of anti-HCV antibody in the leprosy patients is similar to the results of another research reported from National Leprosarium Oku Komyo-En. We, therefore, conclude that the prevalence of anti-HCV antibody in leprosy patients is higher than that of the general population and that anti-HCV antibody is related closely to chronic hepatic dysfunction. Some investigators have recently reported that there was an increased incidence of hepatocellular carcinoma in leprosy patients. And so, it is speculated that this is due to the high prevalence of the hepatitis C virus. However, the reason for this high prevalence of anti-HCV antibody in the sample is obscure.