A rare and striking echocardiographic finding with color-flow Doppler--visualization of intercoronary collaterals within the ventricular septum--in an asymptomatic 5-year-old girl is reported. It strongly suggests anomalous origin of the left coronary artery from the pulmonary artery. Several additional echocardiographic features can secure the diagnosis and allow one to proceed with surgical correction without confirmatory cardiac catheterization and angiocardiography. The ages of our patient and of the seven cases reported previously suggest that these collaterals will more likely be identified beyond infancy and in relatively asymptomatic patients with this congenital anomaly.