Background and aim: Epicardial adipose tissue (EAT) is easily quantifiable visceral adipose tissue that is closely associated with cardiometabolic disease including heart failure with preserved left ventricular (LV) ejection fraction. As body fat distribution and metabolism are different between men and women, we evaluated the sex difference in EAT thickness and its relationship to cardiac function. Methods and results: A total of 152 consecutive patients (76 men) with mean age of 62 +/- 9 years were enrolled. Conventional echocardiography was performed and EAT thickness was measured perpendicularly on the right ventricular free wall at end systole. Mean EAT thickness in all patients was 6.5 +/- 2.0 mm. EAT thickness was associated with patient age, body mass index, and the presence of hypertension. EAT thickness was not different by sex in patients younger than 60 years (men, 6.4 +/- 2.0 mm; women, 6.2 +/- 1.8 mm, p = 0.716); however, among patients aged 60 years or older, EAT thickness was significantly greater in women than men (men, 6.0 +/- 1.7 mm; women 7.7 +/- 2.1 mm, p < 0.001). LV function represented by E/e' and s' was significantly related to EAT thickness only in women (E/e', beta = 0.330, p = 0.002; lateral s', beta = +/- 0.225, p = 0.042). Conclusion: EAT thickness was greater in women than men after 60 years old and its relationship with LV function was significant only in women. Greater increase in EAT thickness in elderly women after menopause might partially account for this difference. (C) 2016 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.