A 6-year-old girl with truncus arteriosus type A3, one of the rarest anatomic types, underwent corrective surgery using a cryopreserved valved pulmonary homograft. The special anatomic features in this case were individual origin of the pulmonary arteries. The right pulmonary artery came directly off the truncal vessel, whereas the left pulmonary artery was connected to the aortic arch via a stenotic ductus or ductus-like vessel. The preoperative pulmonary blood flow distribution was 94% on the right versus 6% on the left side. The underperfusion of the left lung may have been related to pulmonary hypoplasia due to long lasting stenosis at the left pulmonary artery take off. The postoperative pulmonary blood flow distribution was 67% on the right versus 33% on the left side. The operative and postoperative course has been uneventful; presently, 6 months after the operation, the patient is in improved clinical condition.