With the ligation of a patent ductus arteriosus by Gross in 1938, surgeons first entered the field of congenital heart disease, and treatment of the patent ductus is representative of the rapid advance made in thoracic surgery in the last 40 years. We have had clinical experiences about 36 cases of this in the department of Thoracic & Cardiovascular surgery, Pusan Paik Hospital, Inje medical college from March 1891 to June 1987. And the results were summarized as follows. 1. There were 11 males, 25 females. The age range of the patients were from 8 months to 36 years with the mean age of 7.9 years. 2. The chief complaints of the patients on admission were frequent URI[50%], dyspnea on exertion[29.8%], chest pain[11.1% k 1%], growth retardation[2%], cough[2.8%], anorexia[2.8%]. But there were 11 patients[30.6%] having no subjective symptoms. 3. In auscultation, the usual continuous machinery murmur was noticed in 30 patients[83.3%], only systolic murmur in 6[16.7%]. 4. In the preoperative chest P-A views, there were noticed cardiomegaly in 20 cases, enlarged pulmonary conus and / or pulmonary plethora in 22 patients[61.1%]. 5. In the preoperative EGG findings, there were noticed pattern of LVH in 8 patients[22.2`], RVH in 2[5.6%], BVH in 4[11.5%] and normal in 19[52.89o]. 6. The size of PDA[mean] was 9.5 mm[length] and 8.8 mm[width], the range of length was from 4 to 29 mm and the range of width was from 4 to 18 mm. 7. There were noticed 6 cases which were combined with other anomalies[VSD in 2 cases, Coarctation of aorta in 2, Mitral regurgitation in 1, and AP window in 1]. 8. On operation, simple ligation of the ductus was performed in 30 cases[83.3%], division and suture-ligation in 5[13.9%]. 9. Postoperative complications were noticed in 4 cases[pneumonia in one case, wound infection or disruption in 3], but there were no mortality.