A right aortic arch is an anatomic variant only occurring in approximately 0.1% of the population. A mirror-image right artic arch without congenital cardiac anomaly is fairly uncommon. We report on a rare case of dysphagia due to isolated aortic diverticulum in a mirror-image right aortic arch. A 72-year-old man presented with dysphagia which was due to posterior compression of the esophagus by a dilated aortic diverticulum. There was no vascular ring and we thought that the pathology was atherosclerotic dilatation of the diverticulum. Graft replacement of the diverticulum was sufficient to relieve his symptom.