Abstract: Persisient infection with hepatitis C Virus (HCV is associated with chronic hepatitis and cirrhosis which may eventually develop into primary hepatocellular carcinoma. The mechanism of pathogenesis is illdefined and nothing is known of the distribution, frequency or type of infected cell in the liver of HCV-infected individuals. In this study we have examined liver tissue taken at autopsy from 2 anti-HCV-positive patients by in situ hybridization for the presence of HCV RNA. Viral RNA was detected by autoradiography after hybridizaiton with 125I-labelled riboprobes. reprsenting approximately 35% of the HCV genome. Only a few positive cells were indentified in the HCV-infected liver samples. but not a normal liver sample. Hybridizaiton with an unrelated probe was negative in all samples. The HCV RNA-positive cells were detected with anti-sense but not sense RNA probes, suggesting that they contained a high ratio of genomic:antigenomic RNA. The appearance and distribution of the HCV RNA-positive cells suggested that they were not hepatocytes and were more likely to be lymphocytes or macrophages.