We identified predictors of mortality in patients with preserved ejection fraction (EF) and clinical heart failure (HF). Although diastolic HF is common, the factors that predict mortality have not been clearly defined. We studied 988 patients with HF and preserved EF enrolled in the Digitalis Investigation Group (DIG) trial. Survival analyses were employed to identify variables associated with mortality. During 3.1 years of follow-up, 231 (23%) patients died. Among 18 variables considered, the strongest independent predictors of death were glomerular filtration rate (adjusted hazard ratio for one standard deviation decrease 1.50, 95% confidence interval [CI] 1.35 to 1.67, p < 0.0001), New York Heart Association functional class III or IV (adjusted hazard ratio 1.64, 95% CI 1.20 to 2.18, p = 0.0011), male gender (adjusted hazard ratio 1.71, 95% CI 1.26 to 2.32, p = 0.0005), and older age (adjusted hazard ratio for one standard deviation increase of age 2 1.28, 95% CI 1.08 to 1.50, p = 0.0019). A risk score was developed to estimate long-term mortality. Diastolic HF is associated with a high death rate. Important predictors of death include impaired renal function, worse functional class, male gender, and older age.