The incidence of acute viral hepatitis among Rochester, Minn, residents 1971-1980 was 28.6 per 100,000 person-years (p-y) (age- and sex-adjusted to the 1980 white population in the United States). The adjusted incidence of hepatitis B (12.9 per 100,000 p-y) was somewhat less than for hepatitis non-B (15.6 per 100,000 p-y). Each type was more frequent among young adults, especially males. The incidence of hepatitis was greater among those employed in the health service industry than among nonmedical employees (53.4 vs 20.0 per 100,000 p-y). Medical employees had nearly a fivefold increased incidence of hepatitis B and a twofold increased incidence of hepatitis non-B. Exposure to known hepatitis cases was common, but other possible causative factors were not frequent. In this midwestern community, the incidence of acute viral hepatitis is substantial, with medical employees at significantly increased risk.