Anomalous origin of the left coronary artery (LCA) from the pulmonary artery (ALCAPA) is a rare cause of ischemia, heart failure and/or sudden death. A premortem diagnosis beyond early childhood is exceedingly rare because over 90% of untreated infants die in the first 12 months of life. We present a case of an asymptomatic fourteen-year old male with ALCAPA diagnosed by multidetector computed tomography (MDCT) angiography, who was successfully treated by surgical coronary transfer of the ALCAPA with reimplantation of the LCA to the aortic root.