Results are presented from a 9- to 12-yr mortality follow-up of 8,427 white adults in six U.S. cities between 25 and 74 yr of age at enrollment. Survival analyses were performed for all causes on 941 confirmed deaths, and for specific primary causes for the subset of 851 death with death certificates. Relative level of FEV1 compared with predicted was a strong predictor of sex-specific chronic obstructive pulmonary disease (COPD), cardiovascular (CV), and all-cause mortality, even after adjusting for age, respiratory symptoms, and smoking. Even in this relatively large cohort, the total number of respiratory deaths was small, and no trend in COPD mortality could be determined over the period of study.