Seventeen cases of palliative right ventricular outflow tract reconstruction were reviewed to determine the optimal outflow diameter in this procedure. The clinical diagnoses of these 17 patients were pulmonary atresia with ventricular septal defect in 8, tetralogy of Fallot (TOF) in 7, TOF with complete atrioventricular canal in 1, double outlet right ventricle with pulmonary stenosis in 1. Techniques of reconstruction were transannular patch in 7 (valved 2, non-valved 5), extracardiac conduit in 5 (valved 2, nonvalved 3), outflow patch in right ventricle in 3, and others in 2. Pulmonary artery growth was not related to the diameter of reconstruction of outflow and postoperative Pp/Ps. The pressure in pulmonary artery tends to be hypertensive when the outflow diameter was more than 90% of the normal value. On the other hand, the minimal outflow diameter in nine cases of primary repaired TOF was in the range of 0.41 to 0.68 (mean of 0.59). In conclusion, the diameter of outflow reconstruction should be 60 to 80% of the normal pulmonary valve.