SEN virus (SENV) is a new, mostly parenterally transmitted, hepatotropic agent. The prevalence of SENV among patients undergoing maintenance hemodialysis (HD) in Poland, as well as risk factors for the infection are not established. Serum samples of 91 patients receiving maintenance HD in Białystok were tested for the presence of strain H SENV (SENV-H) DNA by means of polymerase chain reaction. Fifty-one non-dialysis subjects, age- and sex-matched with the HD patients, mostly with chronic kidney diseases (96%), without hepatitis B (HBV) and C (HCV) or the history of blood transfusion and donation served as controls. SENV-H viremia was prevalent in 40% of HD patients and in 2% of control subjects (p < 0.0001). On multivariable logistic analysis, neither age (63.1 +/- 13.2 years), gender (49% females), dialysis vintage (29, 2-200, months), previous transfusions of packed red blood cells (84%) or fresh frozen plasma (4%), seropositivity for HBs antigen (13%), HCV antibodies (23%) or HCV RNA (17%) were independently associated with SENV-H prevalence in HD patients (chi2 for the model = 13.3, p = 0.103). No associations between SENV-H status and clinical or biochemical markers of liver disease, including serum aminotransferases levels were observed. In conclusion, SENV-H viremia is widespread among patients receiving maintenance HD in north-eastern Poland. Risk factors for its occurrence are equivocal; the infection may well be transmitted by parenteral and feco-oral routes. SEN virus is not directly responsible for liver damage in maintenance HD patients.