We investigated the characteristics and detection rates of SEN virus (SENV) infection among 100 Turkish patients who had with high alanine aminotransferase (ALT) and aspartate aminotransferase levels but were negative for HBV DNA and HCV RNA and had no history of transfusion. As a control group, we also analyzed 50 healthy individuals who had normal ALT levels, were negative for HBV DNA and HCV RNA, and had no history of transfusion. The serum samples of patient and controls were analyzed by PCR to detect the presence of SENV DNA and its two genotypes (SENV-H and SENV-D). We detected SENV DNA in 13 of 100 (13%) patients. Five of 13 (38.46%) patients were positive for SENV-D and 8 of 13 (61.53%) patients were positive for SENV-H DNA. We also detected SENV DNA in 5 of 50 (10%) patients in the control group. Two of 5 (40%) patients were positive for SENV-D and 3 of 5 (60%) patients were positive for SENV-H DNA in the control group. SENV was detected at almost the same frequency in the patient and control groups. SENV did not seem to contribute to the pathogenesis of liver disease (P > 0.05) in this cohort. Our results also showed that SENV transmission was not only associated with blood transfusion but also with some other possible routes.