Respiratory distress syndrome (RDS), formerly known as hyaline membrane disease, occurs in incompletely developed lungs and is, therefore, primarily a disease of preterm neonates. Immature lungs are functionally deficient in mature surfactant. ----- Lung atelectasis leads to ventilation-perfusion disorder, hypoxia, and eventual respiratory failure in the untreated infant who has RDS. A preterm infant must have clinical signs of respiratory distress, which are tachypnea, nasal flaring, chest wall retractions, expiratory grunting and central cyanosis, and a classic chest radiograph that shows diffuse atelectasis and the classic „ground glass“ appearance of the lung fields, to be diagnosed with RDS. ----- Antenatal steroids are believed to decrease the incidence of RDS by accelerating maturation of the fetal lung. Surfactant replacement therapy has been approved for use since 1990 and has been successful in decreasing rates of RDS. In general, prophylactic use of surfactant is recommended over rescue treatment in infants at high risk for developing RDS. The push toward use of less invasive ventilation strategies in the treatment of the RDS has led to several trials of nasal continues positive airway pressure (CPAP). The most current evidence supports the strategy of early CPAP, initiated at birth, with rescue surfactant therapy if indicated. That strategy appears to be superior to prophylactic intubation, surfactant administration and ventilation in preterm infants.