Anomalous origin of the left coronary artery from the pulmonary artery (ALCAPA) is a rare congenital anomaly. This anomaly occurs in approximately one in 300,000 live births. Of the children diagnosed with this syndrome, 90% die within the first year of life because of myocardial ischemia and left ventricular failure. Survival into adulthood is rare and depends upon pre-existing or rapidly developing collateral vessels between the right and left coronary artery. This report concerns the surgical case of anomalous origin of the circumflex coronary artery from the left pulmonary artery complicated with atrial septal defect (ASD). A 34-year-old woman was admitted because of dyspnea on exertion. Echocardiography revealed normal cardiac function with secondary ASD. Coronary catheterization revealed an anomalous origin of the left circumflex coronary artery from the left pulmonary artery. Direct closure of the ASD and coronary artery bypass grafting for the circumflex coronary artery using an internal thoracic artery were performed, and the orifice of the circumflex coronary artery was ligated. The postoperative outcome was excellent. Most of the ALCAPA cases shows the main trunk of the left coronary artery arising from the pulmonary artery. This case demonstrates only the left circumflex coronary artery originating from the left pulmonary artery. Moreover ASD coexisted in this case. To the best of our knowledge, this is a very rare case of its type to be diagnosed and reported.