Orthotopic liver transplantation (OLT) was performed for liver failure related to hepatitis non-A, non-B (HNANB) or hepatitis C (HCV) infections in 12 patients. Of those, 8 patients had chronic and 4 acute hepatic failure. To determine the incidence of recurrent infection, the clinical course, histological findings and serological HCV markers (HCV-RNA and detection of anti HCV antibodies, respectively) were comparatively studied in these patients. Recurrent infection was apparent in 5 of 6 patients transplanted for liver cirrhosis attributable to chronic HCV infection and with HCV-RNA detectable in serum. The clinical course of infection after OLT varied considerably. Chronic active hepatitis, progressing to liver cirrhosis 13 months postoperatively and an acute hepatitis, resolving spontaneously were seen in one case each. Recurrent infection led to chronic persistent hepatitis in the remainder. None of the patients with acute liver failure experienced recurrent infection. HCV-RNA was detectable in all the patients after OLT, with HCV-RNA present pretransplant, however the presence of HCV-RNA in serum was not necessarily associated with clinical illness.