A four year-old boy with an anomalous origin of the left coronary artery (LCA) directly from the right pulmonary artery was reported. He had been underwent to mitral valve replacement by a St Judes no. 29, due to severe mitral insufficiency, secondary to an extensive myocardial infarction including the anterior and posterior papilary muscles, beside the implantation of the LCA in the aorta. Instead of this favorable outcome, it's emphasized the need for earlier recognition to avoid risk sequelae.