Since the introduction of the intensive perinatal care, the surviral rate of the infants weighing less than1500 gm at birth has improved substantially. However, pulmonary disease remain to be the major causes of the highmortality of these low birthweight infants. In order to systematically assess an epidmiologic distribution of thepulmonary diseases in these very low weight prematures, we have analyzed the chest x-rays of 102 infants weighingless than 1500gm. These consisted of 30 with extreme low birth weight (ELBW) weighing less than 1000gm and 72 withvery low birth weight (VLBW) weighing 1001-1500gm. The survival rate of ELBW and VLBW was 10% and 49%,respectively. Seventy of 102 infants had abnormal findins in the chest x-ray. Forty-eight had idiopathicrespiratory distress syndrome (IRDS), 8 immature lung, 6 Wilson-Mikity syndrome, 4 pneumonia, 2 pulmonaryhemorrhage, 1 congenital heart disease, and 1 suspicious Pierre-Robin syndrome. Seven out of 48 infants with IRDShad persistent ductus arteriosus, and in only 2(30%) of 7 cases were alive. Endotracheal intubation and assistedventilation application for the treatment of IRDS resulted in pulmonary interstitial emphsema in 4 infants andpneumothorax and/or pneumomediastinum in 4 infants. Displacement of endotracheal intubation showed lobar and/orintubation tube into the esophagus resulted in air isophagogram and worsened lung aeration. In spite of thedevelopment of many sophisticated methods of diagnostic radiology, the chest x-ray was still the most valuable yetsimple way of evaluating the pulmonary problems in these extreme and very low birth weight prematures.