Among HFpEF patients, higher sST2 levels were associated with the presence of diabetes mellitus; atrial fibrillation; renal dysfunction; right ventricular pressure overload and dysfunction; systemic congestion; exercise intolerance; and biomarkers of systemic inflammation and fibrosis, neurohumoral activation, and myocardial necrosis (<i>P</i><0.05 for all). sST2 was not associated with left ventricular structure or left ventricular systolic or diastolic function.