Outbreaks of hepatitis E (i.e., enterically transmitted non-A, non-B hepatitis) have occurred in some parts of the world and have generally been related to contaminated water supplies. Until recently, when research-based serologic tests (1,2) were developed to test for antibody to hepatitis E virus (anti-HEV), no serologic test was available to identify HEV infection, and diagnosis depended on a history of exposure in an appropriate epidemiologic setting and the exclusion of other causes of viral hepatitis. During 1989-1992, acute HEV infection was documented among six persons in the United States who had returned from international travel. This report summarizes CDC's serologic documentation of acute HEV infection--presumed to have been acquired during international travel--in four of these persons.