Fire fighters are known to be occupationally exposed to many toxic substances. However, the limited number of previous studies has not demonstrated any consistent excess mortality from diseases of a priori concern, such as lung cancer, non-malignant respiratory disease, and cardiovascular disease. We studied 2,289 Seattle fire fighters from 1945 through 1983, and observed 383 deaths. Excess mortality from leukemia (SMR = 503, n = 3) and multiple myeloma (SMR = 989, n = 2) was observed among fire fighters with 30 years or more fire combat duty. Lung cancer mortality was elevated (SMR = 177, n = 18) among fire fighters 65 years old or older. We also analyzed the data by considering fire fighters at risk only after 30 years from first exposure. In this analysis, a trend of increasing risk with increasing exposure was observed for diseases of the circulatory system. For this cause of death, fire fighters with 30 years or more fire combat duty had a relative risk of 1.84 compared to those with less than 15 years of fire combat duty.