A cohort of 184 men from socioeconomically advantaged ancestors has been followed from ages 18 to 65. In order to test the hypothesis that ancestral longevity would predict both mental and physical vigor, the men's physical and psychosocial health have been prospectively monitored, and the age at death of their parents and grandparents obtained. Ancestral longevity was strongly predictive of chronic illness at age 60 +/- 1 years and mortality at age 68 +/- 1 years. Long-lived ancestors, however, exerted little effect in predicting psychosocial vigor and mental health at age 65.