Background: Diastolic dysfunction is known to be found more frequently in female patients. This study was designed to determine gender difference in the relationship between obesity and heart failure with preserved ejection fraction (HFPEF). Methods: We interrogated the Korean Acute Heart Failure (KorHF) Registry database composed of 3,200 patients, which enrolled hospitalized patients with acute decompensated HF. We analyzed 559 patients with available data among 743 patients (26.1% of the KorHF Registry) with HFPEF to match age. Echocardiographic data including systolic and diastolic cardiac function were analyzed. Obesity was defined as BMI ��� 25kg/m2. Results: In overall subjects, mean age was similar between female and male group (68.9짹13.2 vs. 67.6짹13.1 years, p=0.21). Mean value of left atrial (LA) volume index (45.2짹42.5 vs. 34.1짹16.4 ml/m2, p=0.037), A velocity (0.89짹0.36 vs. 0.77짹0.45 m/sec, p=0.011) and E/E��� ratio (18.9짹12.0 vs. 15.1짹8.8, p=0.001) were higher, and E��� velocity (5.34짹2.31 vs. 6.12짹2.22 m/sec, p=0.001) was lower in female group. In sub-group analysis by gender, diastolic parameters of obese and non-obese patients were comparable except A velocity in both gender. In sub-group analysis by obesity, all the parameters were comparable independent of gender in obese group, but female showed diastolic dysfunction compared to male in non-obese group (table 2). Conclusions: In overall subjects with HFPEF, female showed more impaired diastolic function compared to male. However gender difference in diastolic dysfunction in patients with HFPEF was obscured by obesity.