The efficacy of pegylated interferon (p-IFN) and ribavirin (RB) in transplant patients is not well known. Chronic hepatitis C evolves in a more aggressive form after transplantation, causing a worse survival. Twenty-one naïve patients with recurrent chronic hepatitis C demonstrated by biopsy were treated for 48 weeks with p-IFN alpha2b (1.5 microg/kg/wk) and RB (>10.6 mg/kg/d). Quantification of RNA was performed (Amplicor Cobas 2.0 Roche) at baseline, 4, 12, 24, 48, and 72 weeks. A qualitative technique was used when quantitative levels were undetectable. At more than 1 year since liver transplantation we did not detect coinfection with human immunodeficiency virus or use steroid treatment. Among the cohort there were 16 men (76.2%). The mean overall age was 52 +/- 12 years. Time from liver transplant to treatment was 1637 +/- 1030 days. They were all infected with genotype 1. Eight patients received cyclosporine and the others tacrolimus. One patient was coinfected with hepatitis B virus and was receiving lamivudine. The mean initial histological activity index was 6.9 +/- 1.5 and fibrosis, 2.52 +/- 1.8 (Ishak). Two patients needed spleen embolization before the treatment. Two patients had to stop the treatment: one due to clinical intolerance, and the other one due to a cholangitis. In 14%, p-IFN doses were adjusted. In 32% RB was adjusted. Five (23.8%) did not respond at 24 weeks. Fourteen (66.7%) showed end-treatment responses but four relapsed at 72 weeks. A sustained viral response was achieved in 9 (42.8%). One patient died due to arterial thrombosis just after completing the treatment.