HCV is the principal etiologic agent of post-transfusion (PTH) hepatitis. The incidence and course of HCV hepatitis in liver transplant recipients is not well established. To resolve this information deficit, all records of recipients of single liver transplant (OLTx) between March 1986 and March 1990 at the University of Pittsburgh in whom both the donor and recipients' pre-OLTx sera were available (n = 516) were reviewed. All sera were assayed for HCV antibody using a second generation ELISA method developed by Abbott Laboratories. On the basis of the anti-HCV status of the donor and recipient pre-OLTx sera, four groups could be classified: group I (donor-, recipient-) n = 375; group II (donor-, recipient+) n = 111; group III (donor+, recipient-) n = 25; and group IV (donor+, recipient+) n = 5. Post OLTx liver biopsies were obtained for a clinical indication in 473 of these 516 patients. The prevalence of anti-HCV among recipients pre-OLTx was 22.5% (116/516) which is three times greater than the 5.8% (30/516) prevalence in the donors. Histologic hepatitis not ascribable to any cause other than HCV occurred in 76/516 (15%) recipients: 42 in group I; 28 in group II; 6 in group III and none in group IV. The overall risk of HCV hepatitis at 6 months, 1 year and 2 years post-OLTx was 4.8% (25/516), 7.6% (39/516) and 10.1% (52/516), respectively. At each of these time intervals, no significant difference between groups for the prevalence of HCV hepatitis was evident.(ABSTRACT TRUNCATED AT 250 WORDS)