Origin of both coronary arteries from a branch of the pulmonary artery is rare and has not been reported as a cause of sudden unexpected death. We report autopsy findings of a 14-day male infant in previously good health who died suddenly. From the proximal right pulmonary artery arose a single coronary artery, which branched into the right and left main coronary arteries. The right proximal coronary artery coursed between the aorta and pulmonary trunk, and the left main traveled along the anterior proximal aorta. The distal course of the coronary circulation was normal. There was concentric subendocardial healing myocardial infarction. No other congenital anomalies were identified. Total anomalous origin of the coronary arteries from the pulmonary trunk or artery should be considered in cases of sudden unexpected death in infants.