A right aortic arch with aberrant left innominate artery is a rare vascular ring. There have been no successful surgical reports of extremely low-birth weight infants with this anomaly. A 1-month-old girl weighing 0.9 kg was referred to our hospital for surgical treatment of a patent ductus arteriosus. Echocardiography and three-dimensional reconstruction of enhanced chest computed tomography indicated right aortic arch with aberrant left innominate artery encircling the esophagus and the trachea. Transection of the duct, but not clipping, was successfully performed, and the postoperative course was uneventful. This report describes the first successful surgical case of an extremely low-birth weight infant with the very rare vascular ring.