Recurrent hepatitis C virus (HCV) infection is an important cause of fibrosis and cirrhosis after liver transplantation (LT), with histological recurrence developing in at least 50% of patients within the first year. The aim of this study is to assess the safety and efficacy of interferon alfa-2b plus ribavirin in treating histological recurrent HCV after LT. Since 1998, patients with HCV with significant histological recurrence (fibrosis >/= 3 and/or histological activity index >/= 5) or progressive cholestatic disease after LT were treated with interferon alfa-2b (3 million units subcutaneously three times weekly) plus ribavirin (800 to 1,000 mg/d) for 12 months. Immunosuppression was tapered to cyclosporine/FK506 monotherapy. HCV RNA was assessed at entry, week 24, end of treatment, and 6 months after therapy. The primary end point was loss of HCV RNA 6 months after therapy, whereas the secondary end point was histological response. Fifty-four patients met criteria for treatment and have completed follow-up. Patients were mainly men (71% men; mean age, 51 +/- 5 years) with genotype 1 infection (88%) and high viral load (mean HCV RNA, 38 +/- 9 mEq/mL). Dose modification was required in 72% of patients because of cytopenia or side effects. Intent-to-treat analysis showed that serum HCV RNA was undetectable in 19 patients (35%) week 24, 21 patients (38%) week 48, and 16 patients (30%) at the 6-month follow-up. Paired liver biopsy results (before and within 6 months after treatment) were available for 35 patients. Patients who achieved viral eradication had no significant progression of fibrosis after 1 year of therapy. In summary, combination therapy is a reasonable antiviral option for recurrent HCV infection for established post-LT hepatitis and appears to prevent histological progression of disease if viral eradication is successful.