Background/aims: We aimed to compare viral responses to pegylated interferon 2a plus ribavirin with pegylated interferon alpha 2b plus ribavirin. Methods: Patients with the following characteristics were included: anti HCV(+); normal and/or elevated serum transaminase levels; positive HCV RNA by quantitative PCR; and at least stage 1 fibrosis according to Knodell Scoring System on liver biopsy. Patients were assigned into two groups. Group 1 consisted of 37 patients (24 female, 13 male) who received pegylated interferon alpha 2a 180μg s.c. weekly plus ribavirin adjusted for patient’s weight. All patients were genotype 1. Group 2 consisted of 37 patients (27 female, 10 male) who received pegylated interferon alpha 2b 1.5μg/kg s.c. weekly plus ribavirin adjusted for patient’s weight. At week 24, the treatment was discontinued in patients positive for HCV RNA by PCR, while patients negative for HCV RNA continued treatment up to 48 weeks. The end of treatment and sustained virologic responses of the patients were ascertained by assessing HCV RNA levels at the end of the treatment and after 24 weeks follow-up after the cessation of treatment. Results: At week 48, the proportion of patients with negative HCV RNA (end of treatment viral response) was 28/37 (75.7%) in Group 1 and 27/37 (73%) in Group 2. The group sustained virologic response rates were 48.6% and 35.1% for Group 1 and Group 2, respectively. No significant differences were noted between the two groups. Conclusion: The two pegylated interferon molecules were similar in terms of sustained virologic response rate.