To explore dimensions of successful aging, 71 men were selected for healthy adjustment and were prospectively studied in young adulthood (average age 20) and reassessed in 32-year and 48-year follow-ups. Despite an increase of medical problems, most men maintained healthy adjustment in early old age. At both follow-ups, successful young adult predictors of favorable overall outcome included good peer social adjustment, an absence of troubled parental discipline, and an absence of immature defensive behaviors when angry. However, young adult factors were more predictive of outcomes in middle age than in early old age, as predictor effect sizes decreased between the first follow-up and the second follow-up 16 years later. Findings support the possibility of both favorable and unfavorable changes in the second half of life that may diminish the impact of some young adult characteristics and family environments on adjustment in early old age. (Contains 4 tables.)