Background: Previous research indicates that patients with type 2 diabetes are at higher risk of becoming frail. Emerging evidence also indicates that the Mediterranean diet may prevent frailty in the older population. Objective: The aim of this study was to assess whether a Mediterranean-style diet pattern was associated with lower risk of frailty among older women with diabetes. Design: This was a prospective cohort study in 8970 women aged >= 60 y with type 2 diabetes from the Nurses' Health Study. Adherence to the alternate Mediterranean diet (aMED) score was first measured in 1990 and repeated every 4 y until 2010. Frailty occurrence was ascertained up to 2012 and was defined as having >= 3 of the following 5 criteria from the fatigue, resistance, aerobic, illnesses, loss of weight (FRAIL) scale: Fatigue, low Resistance, low Aerobic capacity, having >= 5 Illnesses, and weight Loss of >= 5%. Those with frailty at baseline were excluded. Results: During follow-up, we identified 569 incident cases of frailty. After adjustment for lifestyle factors and medication use, the HR (95% CI) of frailty was 1 for the lowest quartile of the aMED score, 0.88 (0.71, 1.10) for the second quartile, 0.69 (0.53, 0.88) for the third quartile, and 0.54 (0.42, 0.71) for the highest quartile (P-trend < 0.001). A 2-point (similar to 1 SD) increase in the aMED score was associated with a 28% (95% CI: 19%, 36%) reduced risk of frailty. The largest reduction in the risk was observed for a higher consumption of vegetables and fruit, as well as for alcohol intake. Conclusion: A Mediterranean-style diet pattern was associated with reduced risk of frailty syndrome in older women with type 2 diabetes.