The aim of this study was to test the hypotheses that epicardial adipose tissue (EAT) can be a marker of severe coronary artery disease in patients with acute myocardial infarction. Overall, 373 cases who underwent coronary angiography were classified into 2 groups by SYNTAX score: low-score and high-score group. EAT was measured by transthoracic echocardiography. Obtained data were compared using Pearson correlation analyses and univariate and multiple logistic regression analysis. The results showed that EAT in the high-score group was significantly greater than in the normal group (5.6 ± 1.1 vs. 4.1 ± 1.0 mm, P < 0.01). EAT had a positive correlation with SYNTAX score (r = 0.61, P < 0.01). Receiver operating characteristic (ROC) curve analyses showed that EAT could reliably discriminate patients with high SYNTAX score (≥ 33) [AUC: 0.86, 95% confidence interval (CI): 0.822-0.898, P < 0.01]. Multivariate regression analyses showed that EAT was an independent predictor for major in-hospital events. These data showed an association between EAT and SYNTAX score.