The chest radiographs and angiograms were retrospectively evaluated in 47 patients with pulmonary atresia (PA) and ventricular septal defect (VSD) to determine the characteristic findings of major aortopulmonary collateral arteries (MAPCSs) on the chest radiographs. Of 47 patients, 23 had MAPCAs and 24 had only PDA for blood supply of whole right and left lung. Chest radiographs enabled identification of 16 of 23 patients with MAPCAs. The most common finding of MAPCAs was inappropriately large peripheral pulmonary vasculature (n=16, 69.6%). The other findings were tortuosity of pulmonary vasculature (n=12, 52.2%), focal unevendistribution of pulmonary vasculature (n=12, 52.2%), and two descending pulmonary arteries (n=4, 17.4%). When chest radiographs showed two or more findings of MAPCAs, MAPCAs could be differentiated from PDA with statistical significance (p<0.005). It is concluded that chest radiographs may help to identify MAPCAs before angiography if two-dimensional echo ardiography suggests PA with VSD.