Aim: Epicardial adipose tissue (EAT) is a tissue around the heart with visceral adipose properties. It can affect the structure and functions of the myocardium and coronary arteries through inflammatory markers and regulators. The myocardial performance (Tei) index is a parameter capable of globally assessing systolic and diastolic heart functions. This study investigated the relation between EAT thickness and the Tei index. Methods: The study population was selected from patients without structural heart disease. EAT thickness was measured with two-dimensional imaging in parasternal long axis view and from the anterior face of the right ventricle. Tei index measurement was calculated with tissue Doppler echocardiography from the mitral lateral annulus. The relation between the Tei index and EAT was assessed using multivariate linear regression analysis. Results: Forty-three patients (36 female, 7 male; mean age 50.2 +/- 10.6 years) were included in the study. Mean Tei index was 0.39 +/- 0.09, and mean EAT thickness 4.7 +/- 2.4 mm. A significant correlation was determined between tissue Doppler Tei index and EAT thickness at correlation analysis (r = 0.522, P < 0.001). EAT thickness was independently correlated with Tei index at multivariate linear regression analysis (Beta = 0.443, t = 3.522, P = 0.001). Conclusion: EAT thickness is independently correlation with Tei index. Increased EAT thickness may therefore be a predictor of left ventricular dysfunction.