Aneurysm of the left main coronary artery is a rare angiographic finding, with few cases described in the international literature. We report the case of a 42-year-old male with a previous history of acute myocardial infarction, whose coronariography indicated triple vessel coronary disease and an aneurysm of the left main coronary artery. A review of the etiology, clinical aspects, and surgical management of coronary arterial aneurysm is presented.