BACKGROUND: Doppler-estimated peak systolic tricuspid regurgitation pressure gradient (TRPG) is a representative noninvasive parameter for evaluating pulmonary artery systolic pressure, which can be a determinant of adverse outcomes in chronic heart failure with preserved ejection fraction (HFpEF). However, the prognostic implications of TRPG at admission for hospitalized patients with HFpEF are undetermined. METHODS AND RESULTS: We examined 469 consecutive hospitalized patients with decompensated HFpEF (left ventricular ejection fraction ≥ 50%) who underwent TRPG measurement at admission in our HFpEF multicenter registry. The primary outcome of interest was all-cause death. Admission TRPG was significantly correlated with estimated pulmonary capillary wedge pressure and left atrial dimension (r = 0.24, P < 0.001 and r = 0.21, P < 0.001, respectively). During a median follow-up period of 748 (IQR 540-820) days, 83 patients died. Higher TRPG was significantly associated with higher mortality compared to lower TRPG (log-rank; P = 0.007). Multivariable analysis revealed that elevated TRPG was an independent determinant of mortality (HR 1.02, 95% CI 1.01-1.04, P = 0.008) after adjustment for prespecified confounders and renal function. CONCLUSIONS: Elevated TRPG at admission was an independent determinant of mortality in hospitalized patients with HFpEF, indicating that TRPG at admission could be a useful marker for risk stratification in these patients.