Hepatitis E virus (HEV) is the cause of enterically transmitted non-A, non-B (NANB) hepatitis. Water-borne epidemics have been reported in many developing countries primarily affecting young and middle-aged adults. To determine the role of HEV in acute sporadic NANB hepatitis, we have studied the profiles of anti-HEV IgG in the sera of patients previously diagnosed for NANB hepatitis. We tested the sera of 53 patients with acute NANB hepatitis and 100 healthy people as a control group for anti-HEV IgG. Thirty-nine of the 53 patients (73.3%) and none of the control group were positive for HEV infection, according to results shown by ELISA. This result suggests that HEV is a common cause of acute sporadic NANB hepatitis in Turkey. Further studies are needed in the other regions to determine the true prevalence of HEV infection in Turkey.