© 2017 American Society for Nutrition. Background: Although studies to date have confirmed the association between nutrition and frailty, the impact of dietary intake and dietary patterns on survivorship in those with frailty is yet to be examined in a well-powered cohort with validated frailty status. Moreover, previous studies were limited by measurement error from dietary self-reports. Objective: We derived biomarker-calibrated dietary energy and protein intakes to address dietary self-report error. Using these data, we then evaluated the association of mortality in older women with frailty and dietary intake and healthy diet indexes, such as the alternate Mediterranean Diet (aMED), the Dietary Approaches to Stop Hypertension (DASH) score, and the Dietary Inflammatory Index (DII). Design: The analytic sample included 10,034 women aged 65-84 y with frailty and complete dietary data from the Women's Health Initiative Observational Study. Frailty was assessed with modified Fried's criteria. Dietary data were collected by food-frequency questionnaire. Results: Over a mean follow-up period of 12.4 y, 3259 (31%) deaths occurred. The HRs showed progressively decreased rates of mortality in women with higher calibrated dietary energy intakes (P-trend = 0.003), higher calibrated dietary protein intakes (P-trend = 0.03), higher aMED scores (P-trend = 0.006), and higher DASH scores (P-trend = 0.02). Although the adjusted point estimates of HRs (95% CIs) for frail women scoring in the second, third, and fourth quartiles on DII measures were 1.15 (1.03, 1.27), 1.28 (1.15, 1.42), and 1.24 (1.12, 1.38), respectively, compared with women in the first quartile, no overall effect was observed across quartiles (P-trend = 0.35). Subgroup analyses by chronic morbidity or smoking status or by excluding women with early death did not substantially change these findings. Conclusions: The current study highlights the importance of nutrition in older, frail women. Diet quality and quantity should be considered in managing persons with frailty. Am J Clin Nutr 2017;105:1399-407.