Background— Current dietary recommendations for patients with heart failure (HF) are largely based on data from non-HF populations; evidence on associations of dietary patterns with outcomes in HF is limited. We therefore evaluated associations of Mediterranean and Dietary Approaches to Stop Hypertension (DASH) diet scores with mortality among postmenopausal women with HF. Methods and Results— Women’s Health Initiative participants were followed up from the date of HF hospitalization through the date of death or last participant contact before August 2009. Mediterranean and DASH diet scores were calculated from food-frequency questionnaires. Cox proportional hazards models adjusted for demographics, health behaviors, and health status were used to calculate hazard ratios and 95% confidence intervals (CI). For a median of 4.6 years of follow-up, 1385 of 3215 (43.1%) participants who experienced a HF hospitalization died. Multivariable-adjusted hazard ratios were 1 (reference), 1.05 (95% CI, 0.89–1.24), 0.97 (95% CI, 0.81–1.17), and 0.85 (95% CI, 0.70–1.02) across quartiles of the Mediterranean diet score ( P trend=0.08) and 1 (reference), 1.04 (95% CI, 0.89–1.21), 0.83 (95% CI, 0.70–0.98), and 0.84 (95% CI, 0.70–1.00) across quartiles of the DASH diet score ( P trend=0.01). Diet score components, vegetables, nuts, and whole grain intake, were inversely associated with mortality. Conclusions— Higher DASH diet scores were associated with modestly lower mortality in women with HF, and there was a nonsignificant trend toward an inverse association with Mediterranean diet scores. These data provide support for the concept that dietary recommendations developed for other cardiovascular conditions or general populations may also be appropriate in patients with HF. Clinical Trial Registration— URL: http://www.clinicaltrials.gov . Unique identifier: NCT00000611.