We report the cases of two brothers who simultaneously developed myocardial infarction, and in whom we found coronary artery aneurysms at echocardiography. In one case a new surgical procedure was performed. The aneurysm was bypassed by an aorto-coronary vein graft and the coronary ostium of the related coronary artery was closed. Thus, perfusion of the dependent vessels of the aneurysm was maintained, and the risk of distal embolism was prevented. The aetiologies of coronary artery aneurysms are discussed. In our patients the aneurysms were probably congenital, but we cannot exclude the possibility of previously undiagnosed Kawasaki's disease.