Background Heart failure with preserved ejection fraction (HFpEF) accounts for half of heart failure hospitalizations, with limited data on predictors of mortality by sex and race. We evaluated for differences in predictors of all‐cause mortality by sex and race among hospitalized patients with HFpEF in the ARIC (Atherosclerosis Risk in Communities) Community Surveillance Study. Methods and Results Adjudicated HFpEF hospitalization events from 2005 to 2013 were analyzed from the ARIC Community Surveillance Study, comprising 4 US communities. Comparisons between clinical characteristics and mortality at 1 year were made by sex and race. Of 4335 adjudicated acute decompensated heart failure cases, 1892 cases (weighted n=8987) were categorized as HFpEF. Men had an increased risk of 1‐year mortality compared with women in adjusted analysis (hazard ratio [HR], 1.27; 95% CI, 1.06–1.52 [ P =0.01]). Black participants had lower mortality compared with White participants in unadjusted and adjusted analyses (HR, 0.79; 95% CI, 0.64–0.97 [ P =0.02]). Age, heart rate, worsening renal function, and low hemoglobin were associated with increased mortality in all subgroups. Higher body mass index was associated with improved survival in men, with borderline interaction by sex. Higher blood pressure was associated with improved survival among all groups, with significant interaction by race. Conclusions In a diverse HFpEF population, men had worse survival compared with women, and Black participants had improved survival compared with White participants. Age, heart rate, and worsening renal function were associated with increased mortality across all subgroups; high blood pressure was associated with decreased mortality with interaction by race. These insights into sex‐ and race‐based differences in predictors of mortality may help strategize targeted management of HFpEF.