Coronary artery ectasia (CAE) is found in 0.3-5% of patients undergoing coronary angiography. Atherosclerosis is the main cause, followed by Kawasaki disease and infectious emboli. The exact pathogenesis has not been diagnosed as yet, but an inflammatory process is underlying. Symptoms, if present, are usually related to myocardial ischemia. Angiography is the mainstay for diagnosis. The prognosis is generally favorable. Thromboembolic complications are rare with antiplatelet therapy, and spontaneous rupture generally is rare but occurs more commonly in Kawasaki disease. Management varies from antithrombotic therapy to surgical ligation. Controlling coronary heart disease risk factors sharply affects the prognosis in patients with CAE.