There are numerous causes of respiratory difficulty in the newborn, but congenital lobar emphysema, a kind of pulmonary tension disorders, is rare. The patient was a 2-month-old boy who exhibited respiratory distress and cyanosis since 20th day of life. Physical examination on admission revealed labored respiration, tachycardia and intermittent cyanosis when the infant cried or was being fed. Roentgenologic examination disclosed marked radiolucency of the right lung field with shift of mediastinum to the left. The right leave of the diaphragm was depressed and in lateral view, the retrosternal clear space was markedly increased (Fig. 1 and 2). At operation on Feburary 1, 1967, the right upper lobe was hugely enlarged and could not be collapsed. During upper lobectomy the middle and lower lobes were atelectatic but expanded completely at the end of the operation. An anomalous, narrow branching of upper lobe bronchus was thought to be a cause of progressive emphysema (Fig. 3). The postoperative course was smooth and the infant was discharged on the 22nd day. He was well upon clinic visit one and half years later.