An open-label, randomized trial was conducted to compare the efficacy and safety of 2 regimens of interferon-alpha-2a (IFN-alpha-2a) plus ribavirin for management of chronic hepatitis C virus (HCV) infection in human immunodeficiency virus (HIV)-coinfected patients. Sixty-eight patients were randomized to receive IFN-alpha-2a at a dosage of either (1) 6 MU given 3 times per week for 24 weeks, followed by 3 MU 3 times per week for an additional 24 weeks (group A; 31 patients); or (2) 9 MU per day for 2 weeks, followed by 3 MU per day for 22 weeks, followed by 3 MU 3 times per week for 24 weeks (group B; 37 patients). Ribavirin was added at week 16 of therapy if HCV RNA remained detectable at week 12. Sustained virological response was achieved in 10 patients (15%; 6 in group A and 4 in group B). HCV genotypes 2 or 3 and a decrease in the HCV load of >or=3 log(10) copies/mL between inclusion and week 4 were associated with virological response. In conclusion, the combination of conventional IFN-alpha-2a and ribavirin has poor virological efficacy in HCV-HIV-coinfected patients.