Background: Epicardial adipose tissue (EAT) thickness reflects visceral adiposity. Association between visceral obesity and cardiovascular risk was well-established in previous studies. EAT is also associated with coronary artery disease(CAD). Measurement of epicardial adipose tissue (EAT) thickness by echocardiography can be a novel parameter that is inexpensive and easy to obtain and may be helpful not only in cardiovascular risk stratification but also in predicting the severity of CAD. Objective: In this study,we aim to assess the correlation of echocardiographic EAT thickness with the severity& complexity of CAD as denoted by SYNTAX score. Methods: EAT was measured by 2-D echocardiography in 324 patients undergoing coronary angiogram, those who presented with acute coronary syndrome and chronic stable angina. The severity & complexity of CAD was assessed by SYNTAX score from angiography. Results: Epicardial adipose tissue thickness is independently related to coronary artery disease complexity as denoted by SYNTAX scores, and EAT thickness was higher in the high SYNTAX score group. Mean EAT thickness was 10.8± 1.07 mm, 7.8± .87 mm& 3.77± 1.52 mm in the high, intermediate and low Syntax score groups (p<0.0001).At progressivethicknesses (<6, 6–8, and >8 mm), mean Syntax scores were 8.76± 5.45,22.08±4.76,and 31.28±3.22,respectively.EAT thickness had strong and positive correlations with SYNTAXscore(ρ =0.937; p=<0.001)