A large coronary artery aneurysm with fistula to the left ventricle is an uncommon form of coronary artery disease. We describe a 66-year-old man who presented with increasing exertional dyspnea for 2 months. Electrocardiography-gated enhanced multidetectorrow computed tomography angiography was performed. Multiplanar reconstructed and three-dimensional volume-rendered images showed a large right coronary aneurysm and its distal portion which drained directly into the left ventricle.