In recent decades we made an amazing advancement in the area of neonatal respiratory care. The development of exogenous surfactant supplement and many kinds of ventilator support modes for neonate: nasal continuous positive airway pressure (NCPAP), conventional mechanical ventilation (CMV), high-frequency ventilation (HFV) with inhaled nitric oxide gas, Neurally adjusted ventilatory assist (NAVA) system, have improved the outcome for neonates with severe respiratory failure of different causes. However respiratory failure is still a major cause of neonatal morbidity and mortality. Air leak syndrome is one of main cause of respiratory failure which defined as air escapes from intra-alveolar to extra- alveolar areas. The incidence of spontaneous air leak syndrome in premature infants is about 1-2%. Pulmonary interstitial emphysema ( PIE) is a form of air leak syndrome which is usually occurs in infants with poor lung compliance, such as those with respiratory distress syndrome who are being treated with in adequate mechanical ventilation. We described a case of term neonate who developed severe PIE unrelated to mechanical ventilation including CPAP and successfully treated by HFOV care without any invasive procedure. This is the first reported case in Korea. Legends of Figure 1. Chest computed tomographic image of the patient, at the 30 hours after birth. PIE was seen RLL, RML and RUL, extending to the mediastinum and pleural space resulting in pneumomediastinum and right pneumothorax. PIE=pulmonary interstitial emphysema; RLL=right lower lobe; RML=right middle lobe; RUL=right upper lobe