Progress in neonatal intensive care is closely linked to improvements in the management of respiratory failure in small infants. Current modalities of ventilatory assistance range from more benign continuous positive airway pressure (CPAP) to various modes of mechanical ventilation (including high frequency ventilation). The advent of less invasive methods of delivering CPAP has permitted earlier treatment of infants with respiratory distress syndrome and avoided the need for mechanical ventilation. Children's Hospital of New York (Columbia University) places all spontaneously breathing infants on nasal prong CPAP as the first mode of respiratory support. The early initiation of nasal prong CPAP in combination with a tolerance to elevated PCO(2) levels has reduced the incidence of chronic lung disease to <5% in infants weighing less than 1500g. This report will present an historical review and summarize the experience with CPAP at Columbia and other centres. In addition, it reviews the clinical applications and physiological effects of CPAP in preterm infants with respiratory distress syndrome.