The prevalence of hepatitis C virus (HCV) infection in hemodialysis units (HD) is higher than among normal population. Seroconversion was included in many previous studies which constitute a great problem against infection control policies. The aim of this study was to evaluate seroconversion rate and the effect of isolation of hepatitis C positive patients as infection control method. This is controlled prospective study that included 90 patients for 2 years. Isolation policy of hepatitis C positive patients was implemented in the second year of the study. The prevalence of HCV was 48.9% among hemodialysis patients. Seroconversion rate decreased from 15.2% in the first year to 5.1%in the second year after application of isolation. The duration of hemodialysis in months, positive history of blood transfusion and the amount of transfused blood were considered significant factors affecting seroconversion. so we concluded that Isolation of hepatitis C positive patients as an infection control policy is mandatory to control HCV seroconversion in Egypt.