Open surgical ligation has proven to be safe and effective method to bring about closure of patent ductus arteriosus (PDA). The author reviewed the experience with open posterior and lateral thoracotomy for the elective ligation of PDA. A total of 418 patients underwent PDA ligation from January 2000 to December 2004 at Philippine Heart Center. Forty six patients had PDA ligation through small posterior thoracotomy approach by a single surgeon and another 46 patients were randomly selected from 372 lateral thoracotomies. The results showed, on the posterior thoracotomy, male:female ratio was 1:4.75; the age of the patients was 4.19 ± 5.46 years (range, 28 days to 32 years), the mean weight was 21.156 ± 15.381 kg and the operating time, 99.174 ± 28.009 min. There were noted statistically significant differences on the age, weight, duration of operating time and the use of drainage CT with a p-value of 0.002727, 0.016120, 00000 and 0.00001748, respectively. In all cases, the diagnosis was confirmed preoperatively by echocardiography. Open ligation of the PDA was performed by an intrapleural approach. Closure was established with two silk ligatures and no CT drainage of the intrapleural space done depending on the discretion of the surgeon. The total duration of hospitalization was 4.609 ± 2.72 days for posterior thoracotomy and 4.826 ± 3.086 days for the lateral approach. There were no deaths. Successful closure was confirmed by auscultation postoperatively. One patient on each group recanalized with Qp: Qs of < 1 on the posterior thoracotomy but parent opted to be closed anyway and the other patient, the recanalized PDA was closed after 1 month. Minor respiratory complication occurred in 16 and 15 patients, respectively, with no statistically significance. No wound infection developed postoperatively.