INFANT mortality rates have shown spectacular declines in almost every country during this century. The gain in life expectancy has been due to various factors including better understanding and improved management of illnesses in the newborn infant. With increasing survival, attention is now being directed to neonatal morbidity and to the long-term prognosis of those children who survive illness in the neonatal period. It is recognized that infants of low birth weight show increased morbidity rates, but because the management of the small infant is constantly changing, it is necessary to examine the long-term effects, so that the results of current methods of management can continually be evaluated. Although asphyxia and anoxia related directly to the process of birth have been studied extensively in relation to their remote effect on the brain, little attention has been given in this respect to the respiratory distress syndrome (RDS), one of the most