Increased myocardial stiffness in patients with heart failure with preserved ejection fraction (HFpEF) is known to affect diastolic filling. The purpose of this work was to determine if 3D high frequency cardiac MR elastography (MRE) can quantitatively differentiate increased myocardial stiffness in HFpEF patients compared to healthy volunteers. Two patients with clinical diagnosis for HFpEF and 47 healthy volunteers were studied. The myocardial stiffness of HFpEF patients (mean: 10.57 kPa) was found to be significantly stiffer (p < 0.05) than healthy controls (mean: 7.79 kPa). Recruitment of more HFpEF patients is underway for further validation of this finding.