In this study, we evaluated epidemiologic properties, risk factors, clinical course and prognostic factors of 29 newborn babies diagnosed as pneumothorax between January 2003 - March 2005 in Dr. Sami Ulus Children's Hospital Neonatal Intensive Care Unit. Frequency of pneumothorax was 1.3% in hospitalized patients. Predisposing risk factors were detected as pneumonia (n= 13), transient tachypnea of newborn (n= 7), respiratory distress syndrome (n= 5), meconium aspiration syndrome (n= 3), positive pressure ventilatory treatment (n= 5), perinatal asphyxia (n= 5), cardiopulmonary resuscitation (n= 4) and in one patient risk factor was not identified. Most common risk factor was pneumonia in terms while respiratory distress syndrome and positive pressure ventilatory treatment in preterms. Twenty three patients were treated with chest tube drainage. In 13 patients (45%) mechanical ventilation treatment was required. Six patients (20.6%) expired. Presence of bilateral pneumothorax, application of cardiopulmonary resuscitation, and receiving mechanical ventilation were detected as factors increasing mortality (p< 0.05).