AbstractCoronary artery ectasia (CAE) is a well recognized clinical entity encountered during diagnostic cardiac catheterization. The etiopathogenesis of this condition is poorly understood. Due to the frequent presence of associated obstructive coronary artery disease it is considered to be a maladaptive process of atherosclerosis. Based on its association with aortic aneurysm, coronary ectasia is considered to be caused by genetic abnormalities. It is usually not a benign condition, as normal smooth laminar flow is disrupted with a potential of thrombus formation. The role of long‐term anticoagulation in this condition has not been well established. It is speculated that with increasing use of newer, noninvasive modalities the incidence of ectasia may rise, therefore necessitating this review. Copyright © 2007 Wiley Periodicals, Inc.