The present study was undertaken to assess the prevalence of HCV antibodies (anti-HCV) and of chronic liver disease in relatives of anti-HCV positive subjects suffering from chronic active liver disease. We studied 122 subjects from 24 families. Each family had at least one positive anti-HCV component with histologically proven chronic liver disease. Anti-HCV was found in 32% of subjects; 82% of these were suffering from chronic liver disease diagnosed on the basis of physical examination and biochemical parameters. Prevalence of anti-HCV was higher in spouses, parents, and siblings of the index case as compared to the offspring. In conclusion, the transmission of HCV infection and of HCV-related chronic liver disease is contributed to by factors associated with the familial environment.