Pulmonary atresia (PA) and ventricular septal defect (VSD) are usually associated with major aortopulmonary collateral arteries (MAPCAs). Preoperative evaluation of MAPCAs is essential for effective planning of unifocalization. Multidetector-row computed tomography (MDCT) with three-dimensional volume rendering (3D-VR) demonstrates MAPCAs as well as conventional angiography. We report two cases of PA and VSD associated with MAPCAs examined pre- and postoperatively by means of angiography and MDCT with the 3D-VR technique. MDCT with the 3D-VR technique had the potential to elucidate all MAPCAs demonstrated by invasive angiography. This technique is useful with preoperative conventional angiography as a standard examination for the planning of staged surgery.