Trends in mortality among United States Portland cement workers have been evaluated. This study was initiated due to concern about the risks of respiratory and neoplastic diseases associated with employment at cement factories. Workers were selected from 23 cement factories in four geographical locations in the United States. Employees in this study had been employed for at least 5 years prior to 1960 and worked sometime between 1950 and 1960. The study concluded on December 31, 1979, after which the vital status (dead or alive), of each employee included in the survey was determined. Information regarding work history for each individual was obtained from company records. Vital status data was received from the Social Security Administration, Internal Revenue Service, local postmasters, and friends or relatives. A total of 8714 workers were initially identified from company records, but only 5292 met the work history inclusion criteria. Vital status data as of December 31, 1979 was obtained for 5249 of the initial 5292 subjects. The results demonstrated that cement workers mortality rates were often characterized by deficits. In particular, standard mortality ratios for malignant neoplasms, lung cancer, leukemia, and arteriosclerotic heart disease were 0.82, 0.90, 0.68, and 0.83 respectively. Deficits of this sort were also observed for digestive organ cancer, circulatory system and respiratory system diseases. Stomach cancer was the only cause of death which had standard mortality ratios (SMR) greater than the 1.0 reference. For white subjects, the SMR for stomach cancer was 1.33 while for nonwhites it was 1.27. Mortality from stomach cancer was significantly increased in workers who were employed 10 to 19 years in factories using coal and gas. The authors conclude that Portland cement workers are not at increased risk for dust induced respiratory disease, lung cancer, heart disease, or malignant neoplasms.