The purpose of this study was to evaluate the feasibility, tolerability and efficacy of long-term combination therapy with interferon-alfa 2b (IFNalpha-2b) and ribavirin (Rb) for recurrent hepatitis C after liver transplantation. Fifteen patients with histologically confirmed hepatitis C after liver transplantation were treated. After a basic course of 12 months (IFNalpha-2b 3 MU/3 times a week; Rb 3 x 200 mg/day), patients achieving clearance of viremia underwent maintenance therapy with ribavirin (3 x 200 mg/day). Patients without virological response continuously received combination therapy. Levels of HCV RNA, aminotransferases and bilirubin were followed. Therapy led to a significant decline of transaminases and bilirubin in all patients (p < 0.05). Sixty-four per cent of patients had clearance of viremia after 12 months. Sustained virolo gical response was 88%. In patients without virological response, continuation of combination therapy prevented another biochemical relapse of hepatitis. Treatment was accompanied by severe hematological side-effects, requiring medical support in a majority of patients. In two patients (13.5%), therapy finally had to be withdrawn because of major hematological disorders. These results indicate that long-term combination therapy with IFNalpha-2b and Rb is effective in the treatment of recurrent hepatitis C and in preventing further relapse of disease after liver transplantation, but side-effects may require cessation of therapy.