The case is presented of a 31 year old man with anteroseptal myocardial infarction, whose chest X-ray showed an anomalous protrusion along the left cardiac border. After 6 months, the increase in size of such protrusion lead to left ventriculographic and coronariographic examination: the presence of a large nonfistulous bisaccular coronary aneurysm was documented along the anterior descending branch of the left coronary artery. Cardiac surgery consisted in resection of the coronary aneurysm and of the left ventricular post-infarction area, and was followed by good surgical and angiocardiographic result. Histological examination showed the wall of the coronary aneurysm to be composed of collagenous bands in the absence of elastic components, with hemosiderin and fibrino-hematic deposits and scattered granulocytic infiltrates. An infective etiology is hypothesized for the coronary parietal lesion, leading to a coronary pseudo-aneurysm an subsequent myocardial infarction.