Some earlier reports have indicated increased incidence or mortality of specific tumor types in various health care professions. In this study we have evaluated cancer incidence in physicians, dentists, and other health care workers using the Swedish Cancer Environment Register (CER), which was formed by record-linkage between the 1970 census on current occupation and Cancer Register incidence data in 1971-84. In all three profession categories studied an increased risk was found, as well for all malignant tumors combined, as for specific tumor types regarding the different occupations. Possible etiological factors responsible for these risks are discussed.