The optimal immunosuppressive regimen in patients transplanted for hepatitis C (HCV) is still under discussion. High immunosuppression may promote viral replication and recurrent graft hepatitis. But acute and chronic rejection frequently seen in conjunction with HCV recurrence may require some rescue therapy. One hundred and thirty-seven patients transplanted for HCV cirrhosis, who were HCV-RNA positive prior to transplantation, were analyzed. Seventy-nine patients received CSA-based immunosuppression and 58 patients FK506-based immunosuppression. One-month patient survival was 100% in both groups. Three month and 1-year survival rates and the cumulative 1-5-year patient survival was similar in CsA-treated [67/79 (84.8%)] and FK506-treated patients [50/58 (86.2%)]. Retransplantations for HCV recurrence were performed in 5.1% of CsA-treated patients and 6.9% of FK506-treated patients; it was successful in 50% and 75% of patients, respectively. Conversion from CsA to FK506 and vice versa was high with 25 out of 79 patients (31.6%) converting in the CsA group and 8 out of 58 patients (13.8%) converting in the FK506 group. Conversion to FK506 was performed due to acute and chronic rejection and to CsA because of toxicity and HCV recurrence. In both groups, 25% of converted patients died. Five patients of the CsA group and 9 of the FK506 group received OKT3; more than one-third of each group died. Five patients in the CsA group and 6 in the FK506 group received mycophenolate mofetil (MMF) for HCV recurrence or acute and chronic rejection in conjunction with HCV recurrence. All patients of this critical group are alive with good graft function. In conclusion, survival rates of HCV patients were similar to those seen for other indications. Conversion from CsA to FK506 and vice versa was high and reflects a critical group concerning patient survival. OKT3 treatment should be avoided. A promising therapeutic option for critical patients experiencing acute or chronic rejection in conjunction with HCV recurrence may be treatment with MMF.