Background: Frequent transfusion of blood and blood products to patients with thalassemia major and hemophilia and under hemodialysis patients may cause infections such as hepatitis infection in them. This study aimed to determine the prevalence of hepatitis C and associated risk factors in these patients in Isfahan, the second big province in Iran.Methods: In a descriptive study, all the patients with hemophilia and thalassemia and under hemodialysis in Isfahan province were enrolled. A questionnaire, including demographic and risk factors of hepatitis C was completed through a structured interview with closed questions by a trained interviewer for each patient and HCV-Ab test results were extracted from patient records.Finding: In this study, 60of 570 patients with thalassemia major (10.5%), 232 of 350 patients with hemophilia A and B (66%) and 17 of 800 under hemodialysis patients (2.1%) were positive for hepatitis C. Based on Multivariate Logistic Regression model, no independent risk factor was found.Conclusion: Prevalence of hepatitis C in patients with recurrent blood transfusion in Isfahan is high. Since no independent risk factor for hepatitis C disease was found in these three groups, it can be concluded that multitransfusion is the only predictor for hepatitis C.