Previous studies have provided conflicting results on the presence of hepatitis C virus-RNA in saliva. In this study, 23 (62%) of 37 patients tested positive for hepatitis C virus-RNA in saliva, using polymerase chain reaction analysis. A slightly greater proportion had a sporadic rather than a parenteral origin of chronic hepatitis C. These results provide a biological basis for saliva as a possible source of hepatitis C virus (HCV) infection, but do not necessarily imply transmission by this route.