Coronary artery anomalies are a diverse group of disorders with highly variable manifestations and pathophysiological mechanisms. The origin of a single coronary artery from an atretic pulmonary trunk is a rare anomaly. We encountered this in an 8-day-old female newborn. This report should alert the cardiac surgical community to this fatal coronary malformation. Surgeons should bear this anomaly in mind when they face unusual myocardial behavior intraoperatively.