True aneurysms of the coronary arteries are very uncommon. In our institution, from December 1982 to April 1987, in more than 2500 coronarographies, we observed only one case whose angiographic findings revealed a real fusiform aneurysm (at least 3 times the diameter of the original vessel) of the right coronary artery. The same patient exhibited a left anterior descending artery ectasia too, as we already noted in other cases not included in the present report. The other coronary arteries showed no associated lesions. Clinical findings included a previous myocardial inferior infarction and typical precordial effort pain with a basal and stress ECG showing non specific ST-T wave abnormalities. The patient underwent right coronary endoaneurysmectomy with interposition of a saphenous vein graft. Postoperative course was uneventful and 8 months after surgery the patient was asymptomatic, and basal and effort ECG showed no ischemic modification. Control angiogram revealed an optimal anatomical reconstruction with no further evolution of the left anterior descending artery dilatation. The distinction between vessel dilation and an aneurysm is discussed.