Anomalous origin of a single coronary artery from the pulmonary artery is a rare and potentially fatal congenital heart malformation. Although the actual incidence is not known, it is rarer than anomalous left coronary artery from pulmonary artery. In the absence of other important congenital cardiac anomalies, patients with anomalous origin of a single coronary artery from the pulmonary artery typically experience myocardial ischemia in association with the physiological decrease in the pulmonary vascular resistance that typically occurs over the first few months of life. To our knowledge, there have been only three reported cases of successful surgical correction. We describe a very unusual case in which the diagnosis was made intraoperatively during surgery to close a ventricular septal defect.