Secundum atrial septal defect occupies about 10 to 15% of congenital heart diseases, and the surgical accomplishment is outstanding, so that the operative mortality is getting near to zero percent. But, the methods of correction, direct closure versus patch closure are still controversial and there is no absolute method about it. Some surgeons prefer direct closure technique for its simplicity and lesser thrombogenicity but others, afraid of arrhythmia and suture detachment after closure of large defect, prefer patch closure. Usually most surgeons use direct suture technique in small and moderate sized defects and patch closure in large defects. In our hospital, 156 cases of isolated secundum atrial septal defect were closed directly by double continuous over and over suture using 5-0 polypropylene[prolene , regardless their sizes and the amounts of shunt flow. There were no operative mortality and no serious complications such as heart block, suture detachment and embolism.