From 1991 to 1994, we experienced 24 cases of neonatal pneumothorax who were admitted to the Neonatal Intensive Care Unit[NICU , Chosun University Hospital. The Following results were obtained.1 The incidence of neonatal pneumothorax was 0.70%, and there were 8 spontaneous pneumothoraces and 16 secondary pneumothoraces. 2 The clinical manifestation of neonatal pneumothorax was as followed. Male infant was dominant[M:F=2:1 , the onset was within 24 hours in the majority[83% , and the right side[62% was more frequent than the left side. The gestation duration and birth weight show no correlation with underlying neonatal pneumothorax. The pulmonary diseases were meconium aspiration syndrome and hyaline membrane disease, and the incidence of those was 58%. Meconium aspiration syndrome occurred earlier than hyaline membrane disease. Symptoms and signs were tachypnea[46% , cyanosis[21% , irritability[13% , chest retraction[8% and apnea[8% .3 The treatments performed were oxygen therapy[17% , thoracentesis[4% and closed thoracostomy with underwater seal drainage[79% . The Mean duration of air leakage was 11.7 hours, and the mean drainage time was 4.35$pm$1.3day. 4 The overall hospital mortality was 33%, and the rate of complication was 46%. The complications were metabolic acidosis, atelectasis, pleural effusion, pulmonary hemorrhage and pneumonia. We concluded that the prognosis was related to the underlying pulmonary disease.