Left posterolateral incision has been a conventional incision for patent ductus arteriosus ligation. This study aimed to evaluate the efficacy and safety of left axillary thoracotomy for patent ductus arteriosus ligation. Between January 2013 and December 2019, the clinical data of 76 patients who underwent left axillary thoracotomy for patent ductus arteriosus ligation were compared with the data of a paired group of 101 patients who underwent left posterolateral thoracotomy. Compared with the left posterolateral group, the left axillary group showed less drainage (P < 0.05). Operation time, postoperative mechanical ventilation time, and postoperative hospitalization duration were similar between the groups. Complications were rare in both groups with no mortality during follow up. In total, 72 patient families (95%) in the left axillary group and 81 patient families (80%) in the left posterolateral group were satisfied with their cosmetic results (P < 0.01). A left axillary thoracotomy is as safe and effective as a left posterolateral thoracotomy for patent ductus arteriosus ligation. With lower trauma and better cosmetic results, this procedure provides a good alternative to the standard left posterolateral thoracotomy.