Six-year predictors of successful aging were analyzed for 356 Alameda County Study men and women aged 65–95 years measured prospectively in 1984 and followed to 1990. Successful aging was defined as needing no assistance nor having difficulty on any of 13 activity/mobility measures plus little or no difficulty on five physical performance measures. After adjusting for baseline successful aging, sex, and age, the authors found that 1984 predictors of 1990 successful aging included income above the lowest quintile (odds ratio (OR) = 2.01, 95% confidence interval (Cl) 0.99–4.11), >12 years of education (OR = 1.67, 95% Cl 0.98–2.84), white ethnicity (OR = 2.12, 95% Cl 0.93–4.86), diabetes (OR = 0.10, 95% Cl 0.01–0.79), chronic obstructive pulmonary disease (OR = 0.41, 95% Cl 0.17–0.97), arthritis (OR = 0.43, 95% Cl 0.26–0.71), and hearing problems (OR = 0.48, 95% Cl 0.25–0.89). Adjusting for all variables, the authors found that behavioral and psychosocial predictors included the absence of depression (OR = 1.94, 95% Cl 1.10–3.42), having close personal contacts (OR = 1.82, 95% Cl 1.05–3.18), and often walks for exercise (OR = 1.77, 95% Cl 1.00–3.12). Cross-sectional comparisons at follow-up revealed significantly higher community involvement, physical activity, and mental health for those aging successfully. Am J Epidemiol 1996; 144: 135–41.