Occupation as a risk factor for female breast cancer was investigated. A NIOSH database containing 2,971,483 occupationally coded death certificates collected from 23 states between 1979 and 1987 was searched to identify all female breast cancer deaths. The data were used to calculate age adjusted race specific proportional mortality ratios (PMRs) for breast cancer as a function of occupation. In both black and white females, mortality from breast cancer was significantly elevated among those employed in executive, administrative and managerial; professional; and administrative support jobs including clerical work. Breast cancer mortality was also significantly increased for those employed in sales and precision production occupations. Occupations associated with the lowest risk for breast cancer for both white and black females included service, farming, transportation, and laborer. Teachers accounted for more than 5% of the breast cancer deaths in the data set; a case referent study yielded PMRs for breast cancer in all teachers, primary and secondary teachers, and postsecondary teachers of 162, 161, and 186, respectively. The odds ratios (OR) for dying from breast cancer in all, primary and secondary, and postsecondary teachers were 1.76, 1.73, and 2.21, respectively. All PMR and OR increases were statistically significant. The authors conclude that several occupational groups have been shown to have an increased risk of dying from breast cancer. The increased risk cannot be explained solely by workplace Journal Articlefactors. Lifestyle factors are probably involved. This study suggests that occupationally coded mortality data may be useful for identifying groups at risk for preventable diseases.