Munro is generally considered the first person to have demonstrated, in 1888, in an infant cadaver, the feasibility of dissection and ligation of a persistently patent ductus arteriosus. In august, 1938, Robert Gross reported first successful division and suture of the patent ductus of 7 year old girl. Interruption of a ductus is one of the most satisfactory and curative operations in the field of surgery for congenital heart disease. Seventy-eight consecutive cases of closure of patent ductus arteriosus were operated from June 1980 to June 1988 in the department of thoracic and cardiovascular surgery in Maryknoll Hospital. Retrospective clinical analysis of the patients were 1. There were 24 males, 54 females. 2. The age range of the patients were from 7 months to 32 years with the mean age 9.8 years. 3. Chief complaints of the patients were frequent URI[70.5%], dyspnea on exertion[36.9%], palpitation[10.3%], but 15 patients[19.2%] had no subjective symptoms. 4. Continuous machinery murmur could be heard at the 2nd or 3rd intercostal space on the left sternal border in 66 patients[84.6%]. The other 12 patients made systolic murmur. 5. Radiographic findings of the Chest P-A were cardiac enlargement in 55 patients[70%], enlargement of pulmonary conus and/or increasing density of pulmonary vascularity in 68 patients[87%]. 6. Electrocardiographic findings of the patients were within normal limit in 23 patients[36%], LVH in 38 patients[48.7%], RVH in 7 patients[9%], biventricular hypertrophy in 5 patients[6%]. 7. Cardiac catheterization performed in 62 patients. Mean Qp/Qs=2.5, mean pulmonary arterial pressure=45 mmHg. 8. 73 patients were operated through left posterolateral thoracotomy: Closure of the ductus by ligation in 64 cases, division with suture in 6 cases, and division with aortopatch in 3 cases. Ligation through median sternotomy under cardiopulmonary bypass were 5 cases. 9. There was no death associated with operation, but one case was experienced with intraoperative tearing of ductus resulting in massive bleeding. The other complications were transient hoarseness in 2 patients, chylothorax in 2 patients.