Giant coronary aneurysms are defined as dilatation greater than 4.0 cm in diameter, or 4 times the normal diameter of the coronary artery. It is a rare pathology in the general popula-tion and most commonly affects the right coronary artery. The most common etiology of this aneurysm subtype is atherosclerosis. The clinical presentation varies, from asymptomatic to acute myocardial infarction with ST-segment elevation. The present case report describes a patient with acute myocardial infarction that underwent coronary cineangiography, which revealed a giant coronary aneurysm in the right coronary ostium, between the aorta and the superior vena cava, measuring 55 mm in diameter. It was compressing the middle portion of the coronary artery. Subsequently, resection of the coronary aneurysm, correction of the aortic defect resulting from the resection, and right coronary artery bypass graft surgery, using an aortovenous graft, were prescribed.