© 2018 American College of Cardiology Foundation Objectives: This study prospectively examined physical activity levels and the incidence of heart failure (HF) in 137,303 women, ages 50 to 79 years, and examined a subset of 35,272 women who, it was determined, had HF with preserved ejection fraction (HFpEF) and HF with reduced EF (HFrEF). Background: The role of physical activity in HF risk among older women is unclear, particularly for incidence of HFpEF or HFrEF. Methods: Women were free of HF and reported ability to walk at least 1 block without assistance at baseline. Recreational physical activity was self-reported. The study documented 2,523 cases of total HF, and 451 and 734 cases of HFrEF and HFpEF, respectively, during a mean 14-year follow-up. Results: After controlling for age, race, education, income, smoking, alcohol, hormone therapy, and hysterectomy status, compared with women who reported no physical activity (reference group), inverse associations were observed across incremental tertiles of total physical activity for overall HF (hazard ratio [HR]: Tertile 1 = 0.89, Tertile 2 = 0.74, Tertile 3 = 0.65; trend p < 0.001), HFpEF (HR: 0.93, 0.70, 0.68; p < 0.001), and HFrEF (HR: 0.81, 0.59, 0.68; p = 0.01). Additional controlling for potential mediating factors included attenuated time-varying coronary heart disease (CHD) (nonfatal myocardial infarction, coronary revascularization) diagnosis but did not eliminate the inverse associations. Walking, the most common form of physical activity in older women, was also inversely associated with HF risks (overall: 1.00, 0.98, 0.93, 0.72; p < 0.001; HFpEF: 1.00, 0.98, 0.87, 0.67; p < 0.001; HFrEF: 1.00, 0.75, 0.78, 0.67; p = 0.01). Associations between total physical activity and HF were consistent across subgroups, defined by age, body mass index, diabetes, hypertension, physical function, and CHD diagnosis. Analysis of physical activity as a time-varying exposure yielded findings comparable to those of baseline physical activity. Conclusions: Higher levels of recreational physical activity, including walking, are associated with significantly reduced HF risk in community-dwelling older women.