The detection of hepatitis C virus (HCV) in saliva was studied. Twenty-three subjects with chronic HCV infection and 1 subject with acute HCV infection were enrolled in a 21-day study. Roche COBAS Amplicor and Bayer VERSANT HCV RNA qualitative assays were used. For the 23 subjects with chronic HCV infection, 72% of 474 saliva samples were positive (or were imputed to be positive) for HCV RNA. Serum HCV RNA load predicted the detection of HCV RNA in saliva (odds ratio of 378.7 [95% confidence interval, 18.9-9996.6] for each additional log10 value). This association was also observed in 1 subject with acute HCV infection. Thus, our data demonstrate that salivary HCV RNA detection was associated with serum HCV RNA load in individuals who were chronically or acutely infected with HCV.