A substantial proportion of cases of enterically transmitted acute viral hepatitis occurring in young to middle-aged adults in Asia and the Indian subcontinent is caused by the hepatitis E virus (HEV). It is transmitted mainly by contaminated drinking water and is associated with a high mortality rate (up to 20%) in pregnant women. Chronic forms of hepatitis E are not known. An enzyme immunoassay (EIA) for the detection of IgG antibodies to hepatitis E (Abbott), based on two recombinant HEV antigens, yielded repeatedly reactive results in 5 of 250 (2%) blood donors, 13 of 543 (2.4%) healthy employees from four firms in Hamburg, and in 5 of 150 (3.3%) hemodialysis patients. Supplemental testing by two synthetic peptide EIAs and by Western Blot confirmed positive results in 22/23 samples. None of the samples was IgM antibody-positive. Since no transfusion-transmitted cases of hepatitis E have been observed so far, HEV assays seem to be more useful for differential diagnosis of viral hepatitis than for the screening of donors in the blood bank setting.