ABSTRACT: BACKGROUND:The frailty syndrome is associated with higher risk of disability and death after accounting for multimorbidity. Therefore, the determinants of frailty need to be identified to ensure older adults live not only longer but also healthier lives. However, the effect of diet quality on frailty is mostly unknown. OBJECTIVES:We aimed to evaluate the alternate Mediterranean diet (AMED), the Dietary Approaches to Stop Hypertension (DASH) diet, and the alternate Healthy Eating Index-2010 (AHEI-2010) in association with frailty risk among older women. METHODS:We analyzed data from 71,941 women aged ≥60 y participating in the Nurses' Health Study. The AMED, DASH, and AHEI-2010 were computed from validated FFQs in 1990 and repeated every 4 y until 2010. Frailty was defined as having ≥3 of the following 5 criteria from the FRAIL scale: fatigue, reduced resistance, reduced aerobic capacity, having ≥5 illnesses, and weight loss ≥5%. The occurrence of frailty was assessed every 4 y. RESULTS:During follow-up we identified 11,564 incident cases of frailty. After adjusting for potential confounders, the RRs (95% CIs) of frailty per 1-SD increase in the AMED, DASH, and AHEI-2010 scores were 0.87 (0.85, 0.90), 0.93 (0.91, 0.95), and 0.90 (0.88, 0.92), respectively. All diet quality scores were associated with lower risk of the individual frailty criteria fatigue, reduced resistance, reduced aerobic capacity, and weight loss. Lower consumption of red and processed meat, a lower sodium intake, a higher ratio of monounsaturated to saturated fat, vegetables, and moderate alcohol intake were components of the diet quality scores independently associated with lower risk of frailty. CONCLUSIONS:Adherence to a healthy diet, as defined by the AMED, DASH, and AHEI-2010 scores, was associated with reduced risk of frailty in older women.