Recently, with an available serological hepatitis E virus diagnostic kit, the prevalence of IgG antibody to hepatitis E virus among Chinese subjects in Taiwan was evaluated by means of a solid-phase enzyme-linked immunoassay based on two recombinant hepatitis E virus antigens. The overall prevalence of hepatitis E virus antibody was 10.7% among 384 healthy subjects older than 20 yr but only 0.3% among 600 school-children and young adolescents younger than 20 yr (p < 0.0001). Serial serum samples from 32 hepatitis E virus antibody-positive healthy subjects showed 84% of them to have antibodies persisting more than 3 to 8 yr. Among patients with viral hepatitis, IgG hepatitis E virus antibody was detected in 10% of 10 patients with acute hepatitis A, in 9.5% of 63 patients with acute hepatitis B and in 13.9% of 36 patients with acute posttransfusion hepatitis C. Of 77 patients with sporadic non-A, non-B hepatitis, IgG hepatitis E virus antibody was detected in 18.9% of 53 patients positive for antibody to hepatitis C virus and in 45.8% of 24 patients negative for hepatitis C virus antibody (p < 0.03). Most of our hepatitis E virus antibody-positive normal subjects and patients had never been abroad. These findings demonstrate that sporadic or subclinical hepatitis E virus infections also exist among the Chinese subjects in Taiwan. Hepatitis E virus infection may play an important role in patients with hepatitis C virus antibody-negative sporadic non-A, non-B hepatitis. IgG hepatitis E virus antibody in the sera of normal subjects may last for more than 8 yr.