Recurrent hepatitis C virus (HCV) after orthotopic liver transplantation (OLT) frequently causes allograft failure, because viral aggressiveness has been shown to be increased among immunosuppressed patients. Several studies have reported lower efficacy of antiviral therapy after OLT associated with worse tolerability. The aim of this study was to compare the logarithmic falls in viral loads at 4 and 12 weeks of treatment with pegylated interferon alpha and ribavirin among OLT versus immunocompetent patients. OLT patients (group 1) were recruited from 3 Spanish centers. Two age- and sex-matched controls (group 2) were randomly assigned to each case. We excluded coinfection with human immunodeficiency virus or hepatitis B or cholestatic hepatitis. Among group 1 (n = 66) were 72.7% men with an overall mean age of 52.7 +/- 10.1 years; 90.9% were genotype 1. The mean baseline viral load was 6.0 +/- 0.6 log10 IU/mL, and 19% of patients had cirrhosis. Among group 2 (n = 132) were 72.7% men with an overall mean age of 50.1 +/- 10.1 years; 92.4% were genotype 1. The mean baseline viral load was 5.9 +/- 0.5 log10 IU/mL, and 17% of patients had cirrhosis. There were no significant differences in patient characteristics between the 2 groups. The logarithmic falls in viral loads at 4 weeks of treatment were similar in groups 1 and 2: 2.3 +/- 2.1 vs 2.4 +/- 1.9 log10 IU/mL (P = .49); they were also similar at 12 weeks of treatment: 3.9 +/- 1.9 vs 3.7 +/- 2.4 log10 IU/mL (P = .66). In conclusion, in our study HCV sensitivity to combined antiviral therapy was the same among transplant versus immunocompetent patients.