Anomalous origin of the left coronary artery from the pulmonary artery, also known as Garland-Bland-White syndrome, usually occurs as an isolated condition. We report an infant with caudal regression sequence diagnosed with interrupted aortic arch type B and type III aortopulmonary window, who was found to have anomalous origin of the left coronary artery from the right pulmonary artery at surgical repair. Successful repair of the aortopulmonary window and interruption was performed with reimplantation of the left coronary artery into the ascending aorta. This report highlights the importance of closely assessing the coronary ostia in patients undergoing complex aortopulmonary window repair.