Objective: Cord blood is one of the most important sources of hematopoietic stem cells which can be used for transplantation to cure malignant and non-malignant diseases because of lower risk of GVHD. Transplanting CB stem cells might cause infections in recipients. HHV8 is a γ-herpes virus that infects circulating mononuclear cells in blood. This virus is the main agent of Kaposi`s sarcoma and can reject transplantation. It is known that, HHV8 can transfer during sex among homosexual men, saliva in children and blood products.The aim of this study is to verify vertical transmission of HHV8 during pregnancy by cord blood in order to improve usage of cord blood stem cells in all medical aspects. Materials and Methods: To assess the incidence of HHV8 infection by CB, we surveyed 800 cord blood samples of women by the mean age of 26. After extracting DNA of CBMCs (Cord Blood Mononuclear Cells), Real Time PCR was done in 40 cycles for all samples. At the end RT-PCR and Real Time PCR was performed for HHV8 positive CB samples. Results: The overall HHV8 seroprevalence in cord blood mononuclear cells was 1.38% . Only 11 pregnant women represented DNA of HHV8 in their cord blood. Results of Real Time PCR for cDNAs of positive samples demonstrated no lytic phase of HHV8 in our CB samples. Conclusion: Our data illustrate that screening suspicious CB samples and studying on more samples may eliminate risk of HHV8 transmission through CB transplantation.