Objectives: Increased epicardial adipose tissue (EAT) thick- ness is a risk factor for cardiovascular diseases. Previous studies have demonstrated that EAT thickness is increased in patients with hypertension compared with normotensive in- dividuals. In the current study, we aimed to evaluate whether echocardiographically measured EAT thickness differs among patients with normotension, prehypertension, hypertension, and the relation between EAT thickness and blood pressure levels in prehypertensives. Study design: Patients with prehypertension (n=50) and hy- pertension (n=50) and normotensive healthy subjects (n=50) according to the American Hypertension Guidelines (Joint Na- tional Committee 7) were enrolled in the study. All participants underwent transthoracic echocardiographic examination. EAT thickness was measured from the parasternal long-axis view at end-systole. Results: Compared with normotensives, EAT thickness was significantly increased in subjects with prehypertension and hy- pertension (4.1±1.1 mm, 5.4±1.3 mm and 6.6±1.5 mm, respec- tively, p<0.001). After adjustment for confounding factors like age, gender, high-density lipoprotein, waist circumference, and body mass index, EAT thickness in the normotensive, prehy- pertensive and hypertensive groups was measured as 4.3±1.2 mm, 5.3±1.2 mm and 6.4±1.4 mm, respectively (p=0.001). In the prehypertensive group, multivariable linear regression analysis showed that EAT thickness was positively correlated with both systolic (r=0.305, p=0.001) and diastolic (r=0.297, p=0.001) blood pressures, independent of other risk factors. Conclusion: In addition to hypertensive subjects, echocar- diographically measured EAT thickness is increased in pre- hypertensive patients when compared with normotensive subjects, independent of other factors. Additionally, increased EAT thickness is significantly correlated with systolic and dia- stolic blood pressure levels in patients with prehypertension.