IntroductionSuccessful aging as a process of adaptation to the optimal state is little known in older people. ObjectiveTo describe successful aging and to analyze the factors associated with frailty in people aged 86 years. MethodologyA cross-sectional study of a clinical trial at the second year of follow-up (Octabaix Study), of non-institutionalized subjects born in 1924, conducted in seven Primary Care Centers. MeasurementsData on sociodemographic, comorbidity and geriatric assessment scales were collected. Frailty was defined by the presence of 3 or more of the following criteria: muscle weakness, slow walking, weight loss, exhaustion, low physical activity. Successful aging was defined as: Barthel index >90/100 and Lobo test ≥24/35. Multiple regression analysis was performed. ResultsA total of 273 patients were evaluated, 39.2% men. The prevalence of successful aging was 47.2% (129). In the unsuccessful aging, the frailty prevalence was 34.7% (50). The frailty factors associated with unsuccessful aging were low activity (OR: 7.56; 95%CI: 3.8 -14.9), weakness (OR: 6.08; 95%CI: 2.5-14.7), slowness (OR: 5.1; 95%CI: 2.8-9.5), and exhaustion (OR: 3.6; 95%CI: 1.6-8.3). ConclusionThe prevalence of successful aging is high in 86-year-old community-dwelling subjects. The low physical activity multiplied by seven, and muscle weakness by 6, were the factors most associated with unsuccessful aging. Therefore, incorporating screening designed to detect these two factors could improve future interventions towards more optimal aging in the community, if these results are confirmed in future studies.