OBJECTIVE: We examine the importance of anthropometric and performance measures, and age, period, and cohort effects in explaining life expectancies among major league baseball (MLB) players over the past century. METHODS: We use discrete time hazard models to calculate life tables with covariates with data from Total Baseball, a rich source of information on all players who played in the major league. RESULTS: Compared to 20-year-old U.S. males, MLB players can expect almost five additional years of life. Height, weight, handedness, and player ratings are unassociated with the risk of death in this population of highly active and successful adults. Career length is inversely associated with the risk of death, likely because those who play longer gain additional incomes, physical fitness, and training. CONCLUSIONS: Our results indicate improvements in life expectancies with time for all age groups and indicate possible improvements in longevity in the general U.S. population.