Background: One of the main health issues in the world is coronary artery disease (CAD). It frequently causes morbidity and death. From 28.9% in the 1990s to a predicted 36.3% in the 2020s, the global death rate for CAD is anticipated to increase. Objective: The aim of the current study was to confirm the relationship between the epicardial adipose tissue thickness on echocardiography and CAD severity. Patients and Methods: Epicardial adipose tissue thickness (EATT) was measured by echo in 200 patients referred for coronary angio in Ain Shams University between May 2013and October 2014. Results: In our study, diabetic, hypertensive and smoker patients had more significant EATT when compared to non-diabetic, non-hypertensive and non-smoker ones. EATT measured during both systole and diastole was found to be significant in patients with BMI ≥30 and abnormal waist hip ratio when compared to corresponding values of normal BMI and waist hip ratio. On measuring EATT during both systole and diastole, it was found that P-value was significant in high levels of LDL and TGs patients compared to corresponding values in normal levels of LDL and TGs subjects. EATT was highly significant in patients with coronary affection with mean EATT(s) in CAD patients was 6.07 (SD 1.16) compared to 4.22 (SD 0.9) in patients with normal coronaries and mean EATT(d) in CAD patients was 5.77 (SD 1.13) compared to 4.02 (SD 0.9) in patients with normal coronaries. Also, there was a significant correlation between measurements of both systolic and diastolic EATT and the number of diseased coronary artery in CAD patients. Our study showed no significant correlation between gender and EATT measurements during both systole and diastole. Conclusion: A significant correlation exists between EAT and the existence and severity of CAD. It supports the idea that epicardial fat may contribute to the development of CAD, presumably through paracrine or vasocrine pathways. EAT may be evaluated safely and non-invasively by echocardiography, as it may be a component of the normal evaluation of individuals suspected of being at risk for cardiovascular or metabolic disorders.