Background: SEN virus is considered one of the blood-borne viruses. It was discovered by investigators at DiaSorin Biomolecular Research Institute, Saluggia, Italy in their work for searching about viral causes of post transfusion hepatitis which is not due to the hepatitis C virus or hepatitis B virus. These cases have been called “non-A-to-E hepatitis” because they are not due to any other of the well-known human hepatitis viruses. SEN-V has considered one of the most commonly viral infection found in hemodialysis patients (HD). HD patients are prone to acquire parentally transmitted viral infections such as Hepatitis B, Hepatitis C and HIV. They considered a high risk group for acquiring infection by blood borne viruses because the HD materials which have been used in various medical centers are not completely disposable in addition to the fact that the therapeutic interventions are mostly associated with bleeding and blood transfusion. TT virus has been discovered in 1997 in Japan from the bloodstream of patients with post-transfusion hepatitis, and its name referred to the initials of the first patient in whom virus was diagnosed. The name can also indicate a transfusion-transmitted virus; despite transfusions are not the only means of transmission. After that this virus was called Torque Teno, keeping the initials TTV. In a study carried out on dialysis patients in Italy, The prevalence of TTV DNA in dialysis patients was significantly greater (41.7%) than in healthy individuals (10.7%). Concurrent infection with HCV among dialysis patients positive for TTV has been reported. On the other hand, Low TTV frequency and no correlation between TTV and other blood-borne infections have been reported in study on HD patients in Iran, also TTV infection was not associated with high levels of liver enzymes.