Objectives. To assess causes of premature death and whether race/ethnicity or education is more strongly and independently associated with premature mortality in a diverse sample of middle-aged adults in the United States.Methods. The Coronary Artery Risk Development in Young Adults study (CARDIA) is a longitudinal cohort study of 5114 participants recruited in 1985 to 1986 and followed for up to 29 years, with rigorous ascertainment of all deaths; recruitment was balanced regarding sex, Black and White race/ethnicity, education level (high school or less vs. greater than high school), and age group (18-24 and 25-30 years). This analysis included all 349 deaths that had been fully reviewed through month 348. Our primary outcome was years of potential life lost (YPLL).Results. The age-adjusted mortality rate per 1000 persons was 45.17 among Black men, 25.20 among White men, 17.63 among Black women, and 10.10 among White women. Homicide and AIDS were associated with the most YPLL, but cancer and cardiovascular disease were the most common causes of death. In multivariable models, each level of education achieved was associated with 1.37 fewer YPLL (P = .007); race/ethnicity was not independently associated with YPLL.Conclusions. Lower education level was an independent predictor of greater YPLL.