BACKGROUND: Hypertension, identifiable by elevated blood pressure (BP), is a heterogeneous multifactorial disorder. Epicardial adipose tissue (EAT), a special fat depot that is related to visceral fat rather than total adiposity, shares the same microcirculation with myocardial tissue and coronary vessels. Recent studies have identified EAT as an active organ, which secretes several mediators, called adipokines, affecting the vascular system. The aim of this study was to evaluate the potential association between EAT and BP, endothelial function, carotid intima-media thickness (CIMT), and pulse wave velocity (PWV) independent of conventional and novel metabolic risk factors in patients with previously untreated hypertension. PATIENTS AND METHODS: Our study, which has a cross-sectional design, included 107 consecutive untreated hypertensive patients. Vascular status and functions were evaluated using CIMT, PWV, and flow-mediated dilation (FMD) of the brachial artery. The values of BP were obtained both by the traditional auscultatory method using a sphygmomanometer in an office and by ambulatory BP measurement. RESULTS: When we stratified the patients into three groups according to increased EAT values, CIMT (P<0.001), presence of carotid plaque (P=0.026), and BP values (P=0.001) were increased in the higher tertile compared with the lower tertile. FMD of the brachial artery decreased significantly with increasing EAT thickness (P<0.001). There was a significant, strong, and negative association between CIMT and FMD (r=-0.604, P<0.001). CIMT correlated positively to age (r=0.404, P<0.001), EAT (r=0.517, P<0.001), office systolic BP (r=0.241, P=0.016), ambulatory systolic BP (r=0.419, P<0.001), and diastolic BP (r=0.360, P=0.002). FMD correlated negatively to age (r=-0.390, P<0.001), EAT (r=-0.495, P<0.001), ambulatory systolic (r=-0.338, P=0.006), and diastolic BP (r=-0.281, P=0.024). Multivariate linear regression analyses, carried out to identify predictors of CIMT and FMD, showed only age, EAT, and mean ambulatory BP as independent predictors of both CIMT and FMD. CONCLUSION: Our study showed that EAT is an independent factor of adverse changes in CIMT, FMD, and PWV. Future studies, investigating the vascular influence of EAT at the molecular level, may provide therapeutic options to prevent its adverse vascular interactions.