This study was conducted to determine the effect of exercise capacity on all-cause mortality among older individulas (aged ≥65 years). For that purpose, 5,314 male veterans aged 65 to 92 years who completed an exercise tolerance test for clinical reasons were analyzed. A total of 2,137 deaths were documented during a median 8.1 years of follow-up. The results showed an inverse, graded, and independent association between impaired exercise capacity and all-cause mortality risk. For instance, for every 1-MET increase in exercise capacity, the mortality risk was 12% lower for the entire cohort and for both age categories (65-70 years; n=2,560 and >70 years; n=2,754). Analyses according to fitness categories showed that an exercise capacity of >5 METs appeared to be necessary for significant health benefits for those aged ≥65 years. In the subgroup of individuals with 2 exercise evaluations (n=867), improvement in fitness status resulted in a 34% lower mortality risk suggesting significant health benefits with an increase in fitness even at an advanced age. Moreover, fit individuals who drifted into the unfit category maintained 41% lower risk compared with those who were unfit in both tests. These findings suggest that fitness-related health benefits are achieved regardless of age or fitness status and that exercise capacity must be encouraged and considered as important as any other risk factors in older population.