Twelve patients had undergone repair of atrioventricular septal defects. Age at operation ranged from 2.4 years to 17 years[mean, 8.25 years]. Five patients were male and seven were female. Three patients had complete atrioventricular septal defect[Rastelli type A] associated with Down`s syndrome. One of the three patient with complete atrioventricular septal defect had tetralogy of Fallot. Three patients had the intermediate form and seven patients had the partial form. The primum atrial septal defect was closed with pericardial patch. The atrioventricular valve septal commissure[mitral cleft] was closed with pledgeted sutures. Three complete atrioventricular septal defect were undergone by two-patch technique. A crescent-shaped Dacron patch was used to occlude the ventricular septal defect. One patient of partial form was sudden death 5 days postoperatively. There were no another complications after surgery. One patient underwent reoperation for opened mitral cleft 2.5 years postoperatively. New York Heart Association functional class of patients was improved postoperatively.