The present study was aimed to clarify the virologic status, liver histologies, and the results of follow-up liver tests in symptom-free individuals with anti-HCV antibodies and normal liver tests. Forty-nine individuals with normal liver tests and positive second generation anti-HCV antibody assay were entered into this study. Cases with hepatitis C viremia were evaluated for HCV genotype, amount of circulating HCV-RNA, and liver histology and were followed-up for more than one year. Of the forty-nine individuals, 36 had hepatitis C viremia, indicated by polymerase chain reaction (PCR) assay. Liver histology was as follows: 3 had non-specific changes, 25 had chronic persistent hepatitis (CPH), and 8 had chronic active hepatitis (CAH). Twenty-four cases with CPH and CAH developed an elevated AST and/or ALT concentration (> 30 IU/l) between 12 and 32 months of follow-up. The amount of circulating HCV-RNA ranged from 10(2) to 10(7) copies/50 microliters serum. The distribution of HCV genotypes was nearly the same as that for symptomatic CAH. These data suggest that the histological examination and follow-up examination are very important for following symptom-free individuals with hepatitis C viremia because there are some candidates for interferon therapy among them. There are few individuals who will remain healthy among asymptomatic HCV carriers.