Background: The potential of acute and chronic viral hepatitis infections in blood leukocytes is one of the possible risk factors of leukemia. Between hepatitis viruses, HGV is important for unknown mechanism of pathogenesis in affecting the outcome of leukemia. In this research the prevalence of HGV infection was studied for evaluation of the possible role of this viral infection in the pathophysiology of leukemia. Methods: In this study, 100 EDTA treated blood samples were collected for 2 and half a year from different types of leukemia and also healthy control group, respectively. The plasma of these blood samples were harvested and stored at -80°C till laboratory tests were performed. Serological and antigenic markers of HBV, HCV and HGV were analyzed by ELISA methods. The HGV viremia was also studied by an in-house nested-RT-PCR method in plasma samples of patients with leukemia and control population. Results: Anti-E2-Ab was detected in 1(1%) of leukemia patients who has not the history of HBV and HCV infections. HGV-RNA was diagnosed in 4(4%) of patients with leukemia and 1(1%) of control group. Simultaneous infection of HGV-RNA and HBsAg was detected in one of patients with leukemia. Significant difference was seen between the prevalence of HBV infection in leukemia patients and control group (P=0.02). Also significant correlation was detected between sex and the prevalence of HBV infection in leukemia patients (P=0.02). None of studied risk factors of leukemia were not significantly correlated with HGV infection. Conclusion: In this study the low prevalence of active and persistent HGV infections in leukemia patients in comparing with control population was confirmed. Also detection of HGV and HBV co-infection in these patients, announced the need of completed studies in different populations with different hematological malignancies and/or abnormalities, for better therapeutic and laboratory management of these cancers.