We report herein two cases of thoracic esophageal cancer with a right aortic arch. Both cases were elderly males who complained of dysphagia. Computed tomography and aortography revealed a right aortic arch with a mirror-image branching and a diverticulum of the right descending aorta in both cases. They underwent an esophagectomy and a mediastinal lymph node dissection in a left thoracotomy, and we also added a median sternotomy in the second case for a lymph node dissection in the right mediastinum. The ductus arteriosus was divided in the first case, but he died of a rupture of the aortic diverticulum 13 months later. In conclusion, for a successful esophagectomy and mediastinal lymph node dissection, a median sternotomy should be added to the left thoracotomy, while careful attention should also be paid to the aortic diverticulum and the ductus arteriosus.