Hepatitis C virus RNA in serum and liver tissue was examined in seven patients with liver cirrhosis by reverse transcriptase polymerase chain reaction method using primers for 5'-non-coding region. Plus strand HCV RNA were detected in serum and liver tissues in five of five patients who had HCV antibodies (C100-3 antibody and P22 antibody) and were not detected in two of two patients who do not have HCV antibody. Minus strand HCV RNA was detected in liver tissue of five HCV antibody positive patients. These results suggest that HCV are present and replicate in liver tissue in patients with liver cirrhosis.