A B S T R A C TChronic infection with hepatitis C virus is a global health problem that can lead to cirrhosis, hepatic disease and hepatic cancer. One of the standard treatments for hepatitis C genotype 1b is Peginterferon plus Ribavirin for 48 weeks that has different response to treatment. Response to treatment could be influenced by different factors. In this study we aim to evaluate the factors related to response to treatment and the rate of response to treatment with Ribavirin plus Peginterferon in patients with chronic hepatitis C genotype 1b. In this analytical cross-sectional study, 90 patients including 44 male and 46 female with mean age of 38.01±11.10 years with the definite diagnosis of Hepatitis C who were treated with Ribavirin plus Peginterferon were included and followed for 48 weeks. In all patients demographic findings, underlying disease and social habits were recorded. Response to treatment was defined at weeks 12, 24 and 48 and different factors were evaluated between groups. Response to treatment was observed in 68 cases (75.6%), recurrence in 16 cases (16.7%) and treatment cessation in 7 cases (7.7%). Opium was used in 1.1%, alcohol in 7.8% and smoking in 22.2%. Also, hepatitis B in 2.2% and diabetes in 6.7% were observed. There were no significant differences between cases with and without response to treatment regarding age, gender, weight, alcohol use, smoking or diabetes. Results of current study showed that treatment with Ribavirin plus Peginterferon in patients with chronic hepatitis C genotype 1b unlike previous studies accompanies with higher response to treatment (75.6%) and different factors have no significant influence in the response to treatment.