Three preterm infants are described who had respiratory failure immediately after birth. For each, historical factors (extrauterine abdominal pregnancy; ruptured membranes with oligohydramnios for 14 weeks; congenital diaphragmatic hernia) and the initial postnatal course were suggestive of pulmonary hypoplasia. However, with vigorous resuscitation each infant showed rapid improvement in pulmonary status for several hours. Two infants survived with no apparent pulmonary sequelae; the third had almost complete resolution of pulmonary disease but died from gastrointestinal complications. Thus some infants with historical and clinical indicators of severe pulmonary hypoplasia do not have hypoplastic lungs and respond favorably to resuscitation. The causes of the respiratory distress and of its rapid resolution are not known. On the basis of this experience, even infants with historical factors suggesting pulmonary hypoplasia and with postnatal respiratory distress should receive vigorous resuscitation.