The authors report the case of a baby in whom an ectopic left coronary artery arising from the pulmonary artery was suspected on clinical and, in particular, electrocardiographic criteria. M mode echocardiography showed left ventricular dilatation with reduced shortening fraction of the LV internal diameter. 2D echocardiography with a mechanical sector scanner demonstrated the left coronary artery arising from the pulmonary artery. The short axis view of the basal vessels in the left parasternal incidence visualised 2 cm of the left coronary artery arising from the posterior part of the pulmonary artery.