A single coronary artery is an anomaly in which only 1 coronary artery arises from the aortic root, supplying the entire heart. We report the case of a 5-year-old girl in whom a single coronary artery ostium was discovered during a Ross-Konno operation. This patient required extracorporeal membrane oxygenation for postoperative right ventricular infarction due to proximal stenosis of a dominant left circumflex artery in combination with an occluded minor right coronary artery. Rescue stent implantation allowed for recovery of right ventricular function and weaning from extracorporeal membrane oxygenation.