Background: Pegylated interferon (Peg-IFN) and standard interferon (IFN) play a significant role in the treatment of hepatitis C virus (HCV) infection. Biosimilar standard IFN is widely available in Brazil for the treatment of HCV infection genotypes 2 or 3, but its efficacy compared to Peg-IFN is unknown. Objective: To compare the sustained virological response (SVR) rates following treatment with biosimilar standard IFN plus ribavirin (RBV) versus Peg-IFN plus RBV in patients with HCV genotypes 2 or 3 infection. Methods: A retrospective cohort study was conducted in patients with HCV genotypes 2 or 3 infection treated with biosimilar standard IFN plus RBV or with Peg-IFN plus RBV. SVR rates of the two treatments were compared. Results: From January 2005 to December 2010, 172 patients with a mean age of 44 +/- 9.3 years were included. There were eight (4.7%) patients with HCV genotype 2 infections. One hundred fourteen (66.3%) were treated with biosimilar standard IFN plus RBV, whist 58 (33.7%) patients were treated with Peg-IFN plus RBV. Between the two groups, there were no significant differences regarding age, gender, glucose level, platelet count, hepatic necroinflammatory grade, and hepatic fibrosis stage. Overall, 59.3% (102/172) patients had SVR. In patients treated with Peg-IFN plus RBV, 79.3% (46/58) had SVR compared to 49.1% (56/114) among those treated with biosimilar standard IFN plus RBV (p = 0.0001). Conclusion: In patients with HCV genotypes 2 or 3 infection, a higher SVR was observed in patients receiving Peg-IFN plus RBV related to patients treated with biosimilar standard IFN plus RBV. © 2012 Elsevier Editora Ltda.163232236Kim, W.R., Brown, R.S., Terrault, N.A., El-Serag, H., Burden of liver disease in the United States: summary of a workshop (2002) Hepatology, 36, pp. 227-242Grant, W.C., Jhaveri, R.R., McHutchison, J.G., Schulman, K.A., Kauf, T.L., Trends in health care resource use for hepatitis C virus infection in the United States (2005) Hepatology, 42, pp. 1406-1413Bini, E.J., Mehandru, S., Sustained virological response rates and health-related quality of life after interferon and ribavirin therapy in patients with chronic hepatitis C virus infection and persistently normal alanine aminotransferase levels (2006) Aliment Pharmacol Ther, 23, pp. 777-785Poynard, T., McHutchison, J., Manns, M., Impact of pegylated interferon alfa-2b and ribavirin on liver fibrosis in patients with chronic hepatitis C (2002) Gastroenterology, 122, pp. 1303-1313Manns, M.P., McHutchison, J.G., Gordon, S.C., Peginterferon alfa-2b plus ribavirin compared with interferon alfa-2b plus ribavirin for initial treatment of chronic hepatitis C: a randomised trial (2001) Lancet, 358, pp. 958-965Fried, M.W., Shiffman, M.L., Reddy, K.R., Peginterferon alfa-2a plus ribavirin for chronic hepatitis C virus infection (2002) N Engl J Med, 347, pp. 975-982Portaria 639. Anexo I: Protocolo clínico e diretrizes terapêuticas da hepatite viral crônica tipo C (2000) Diário Oficial da União, DF, p. 34. , Ministério da Saúde (Brasil), 26 junClinical guidelines for hepatitis C (2007) Dispõe sobre o Protocolo Clínico e Diretrizes Terapêuticas para Hepatite Viral C, , 2007. Report N°: Portaria N° 34, de 28 de setembro de 2007ID6065503-0. Brasil: Ministério da Saúde. Secretaria de Vigilâncirc;ncia em Saúde. 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