The hepatitis C virus is a common cause of chronic hepatitis after orthotopic liver transplantation (OLT). We evaluated 95 consecutive patients who underwent OLT at our institute between March 1988 and November 1992 and who had a follow-up period longer than 3 months. All patients had a second-generation test (ELISA + RIBA) for HCV antibodies (HCV Ab) before and monthly after OLT; all had a polymerase chain reaction (PCR) test for detection of viral RNA after the operation. Whenever biochemical abnormalities (hypertransaminasemia 2 times the normal range) were seen, a percutaneous liver biopsy was performed. Forty-two HCV Ab+ patients before OLT remained positive after OLT. In this group the PCR test was positive in 32 cases (78.5%). In 13/42 (30.9%) cases (all PCR+) with hypertransaminasemia histological examination showed signs of viral C hepatitis (score of Knodell minimum 3, maximum 12, median 5.5). Of 53 HCV Ab patients before OLT, only 1 became HCV Ab+ and PCR+ 15 months after OLT. In the remaining 52 patients 15 were PCR+. Twenty of 53 patients (37.7%) had a liver biopsy because of hypertransaminasemia: in no case did histology show any signs of hepatitis C. In conclusion, viral C recurs often after OLT for post-hepatitic C cirrhosis. The histological graft lesions are in most cases moderate. We did not observe any deaths related to viral C infection in grafted patients. According to our results post-hepatic C cirrhosis remains a good indication for OLT.