Background: Before the introduction of direct-acting antivirals in the treatment of chronic hepatitis C patients, the combination of peginterferon alpha and ribavirin was the standard therapy. Observational studies that in-vestigated sustained virological response (SVR) rates by these drugs yielded different outcomes. Aims: The goal of the study was to demonstrate real life data concerning SVR rate achieved by peginterferon al-pha plus ribavirin in patients who were treatment-naïve. Study Design: A multicenter, retrospective observa-tional study.Methods: The study was conducted retrospectively on 1214 treatment naïve-patients, being treated with pegin-terferon alpha-2a or 2b plus ribavirin in respect of the current guidelines between 2005 and 2013. The patients' data were collected from 22 centers via a standard form, which has been prepared for this study. The data includ-ed demographic and clinical characteristics (gender, age, body weight, initial Hepatitis C virus RNA (HCV RNA) level, disease staging) as well as course of treatment (du-ration of treatment, outcomes, discontinuations and ad-verse events). Renal insufficiency, decompensated liver disease, history of transplantation, immunosuppressive therapy or autoimmune liver disease were exclusion criteria for the study. Treatment efficacy was assessed according to the patient's demographic characteristics, baseline viral load, genotype, and fibrosis scores. Results: The mean age of the patients was 50.74 (±0.64) years. Most of them were infected with genotype 1 (91.8%). SVR was achieved in 761 (62.7%) patients. SVR rate was 59.1% in genotype 1, 89.4% in genotype 2, 93.8% in genotype 3, and 33.3% in genotype 4 pa-tients. Patients with lower viral load yielded higher SVR (65.8% vs. 58.4%, p=0.09). SVR rates according to his-tologic severity were found to be 69.3%, 66.3%, 59.9%, 47.3%, and 45.5% in patients with fibrosis stage 0, 1, 2, 3 and 4, respectively. The predictors of SVR were male gender, genotype 2/3, age less than 45 years, low fibrosis stage, low baseline viral load and presence of early viro-logical response. SVR rates to each peginterferon were found to be similar in genotype 1/4 although SVR rates were found to be higher for peginterferon alpha-2b in patients with genotype 2/3. The number of patients who failed to complete treatment due to adverse effects was 33 (2.7%). The number of patients failed to complete treatment due to adverse effects was 33 (2.7%).Conclusion: Our findings showed that the rate of SVR to dual therapy was higher in treatment-naïve Turkish pa-tients than that reported in randomized controlled trials. Also peginterferon alpha-2a and alpha-2b were found to be similar in terms of SVR in genotype 1 patients.