This article presents the preliminary results of a follow-up study (1950–1992) of 1,146 subjects (person-years = 30,954; 23,055 for women) receiving compensation for mercury poisoning. In a province of Tuscany in central Italy, severe exposure to mercury occurred during fur hat production. A deficit in all causes of mortality was observed in both sexes, whereas mortality due to cancer was slightly higher than expected. Mortality from stomach cancer was significantly elevated for men and women. A significant excess of lung cancer was observed in women only. Whereas the excess of stomach cancer probably reflects elevated rates in the study area rather than exposure to mercury, the excess of lung cancer mortality does appear to be related to mercury exposure. Smoking habits or other exposures at work do not seem to explain the excess of lung cancer.