Follow-up evaluation was carried out in 109 (86%) of 126 children who required ventilatory support in the newborn period for respiratory failure; the commonest cause of which was the respiratory distress syndrome. The children are currently between 1 and 6 years of age. Their gestational ages ranged from 27 to 42 weeks and their birth weights from 1050 to 4360 g.The number of major abnormalities in the RDS group was small, occurring primarily in infants who were less than 1500 g birth weight, or in children who have had neonatal insults such as asphyxia or hyperbilirubinemia. The survivors of other causes of neonatal respiratory failure are too small in number to make a valid comparison with RDS survivors, but all appear to be developing normally. The data presented here suggest that RDS itself, even in its most severe form, does not in the large majority result in impaired development of the survivors, and that the overall outlook for this group of infants is an extremely encouraging one, and indicates that life-support efforts are warranted.