A pneumothorax can arise in a variety of clinical settings in the operating room, from bleb rupture to iatrogenic injury. Should it expand in size and cause increase in intrapleural pressures with resultant diminished venous return, it becomes referred to as a tension pneumothorax. We report a case of a premature infant presenting for repair of congenital pulmonary airway malformation who suffered an iatrogenic tension pneumothorax during lung isolation with fogarty embolectomy catheter used for single lung ventilation in a neonate.