The hepatitis C virus (HCV) genome was sought in the saliva of 76 chronic HCV carriers (mean age nearly 60 years) in a rural Japanese town, who had high serum titers of c-100 and anti-core second generation antibodies. In 27 samples (27 cases, 36%), the HCV-RNA genome was detected by the reverse transcriptase - polymerase chain reaction with either of two sets of primers covering two regions of the HCV genome: the 5'noncoding region and the region encompassing the putative envelope (E1). Transaminase values at the time of sampling were higher in the patients with than in those without detectable HCV RNA in saliva (p = 0.04 for alanine aminotransferase, p = 0.04 for aspartate aminotransferase; Wilcoxon test). The prevalence of the positivity was higher by 5'noncoding primers (14/59 vs. 15/68). Our data show that the severity and duration of hepatic dysfunction influence the detectability of the HCV genome in the saliva. This has been a controversial point among investigators.