Background: The Dietary Approaches to Stop Hypertension (DASH) diet effectively reduces blood pressure. In observational studies, the association between diets consistent with DASH and risk of coronary heart disease and stroke has been examined with varying results. We hypothesized that diets consistent with the DASH diet would be associated with a lower incidence of heart failure (HF). Methods: We conducted a prospective observational study in 36 019 participants in the Swedish Mammography Cohort who were aged 48 to 83 years and without baseline HF, diabetes mellitus, or myocardial infarction. Diet was measured using food-frequency questionnaires. We created a score to assess consistency with the DASH diet by ranking the intake of DASH diet components and 3 additional scores based on food and nutrient guidelines. Cox proportional hazards models were used to calculate rate ratios of HF-associated hospitalization or death, determined using the Swedish inpatient and cause-of-death registers between January 1, 1998, and December 31, 2004. Results: During 7 years, 443 women developed HF. Women in the top quartile of the DASH diet score based on ranking DASH diet components had a 37% lower rate of HF after adjustment for age, physical activity, energy intake, education status, family history of myocardial infarction, cigarette smoking, postmenopausal hormone use, living alone, hypertension, high cholesterol concentration, body mass index (calculated as weight in kilograms divided by height in meters squared), and incident myocardial infarction. Rate ratios (95% confidence intervals) across quartiles were 1 [Reference], 0.85 (0.66-1.11), 0.69 (0.54-0.88), and 0.63 (0.48-0.81); Ptrend <.001. A similar pattern was seen for the guideline-based scores. Conclusion: In this population, diets consistent with the DASH diet are associated with lower rates of HF. ©2009 American Medical Association. All rights reserved.