There were 850 deaths among 11,071 Seventh-Day Adventist (SDA) men from 1958 to 1962. The group was similar to other men in California except for occupation, an older age distribution, and much less tobacco exposure. The total number of deaths observed and death from respiratory disease were approximately one half and one fourth, respectively, of that expected at comparable ages for California men. In the SDA group, the 28 deaths contributed to by emphysema or lung cancer were concentrated in a minority with a history of heavy tobacco usage; only one such death occurred among 3,913 (35%) SDA "lifetime" members who had never smoked. The findings from this study are consistent with previous epidemiologic studies and predictions of a large reduction in lung cancer and other mortality in any nonsmoking US population. The findings support the causal relationship of cigarette smoking to lung cancer but discount the "selection or constitutional" theory.