Anomalous origin of the left coronary artery from the pulmonary artery is a rare congenital cardiac malformation that is commonly associated with mitral insufficiency. Direct implantation of the anomalous origin of the left coronary artery from the pulmonary artery into the aorta is ideal, but it may not be fit for some patients whose anomalous left coronary arteries arise remotely from the ascending aorta. To solve the same technical problem in a boy with anomalous origin of the left coronary artery from the pulmonary artery in combination with moderate mitral insufficiency, we successfully elongated the anomalous coronary artery by creating a tube-shape graft using part of the pulmonary arterial wall. Simultaneous mitral annuloplasty was performed after a dual-coronary repair.