Confusion of a patent ductus arteriosus (PDA) for the descending thoracic aorta is a fatal error occurring occasionally in infants or neonates. As a result, the left pulmonary artery (LPA) may be misconceived as the PDA, and ligated. This surgical mishap of other hospital leads to serious congestive heart failure and loss of left lung function due to the underdevelopment in the peripheral vascular and alveolar structures in neonates and premature infants. In this report, 3 cases of LPA ligation and subsequent treatment are presented.