Congenital diaphragmatic hernia is a congenital malformation associated with pulmonary hypoplasia. It often leads to respiratory failure, requiring artificial ventilation with high inflation pressures and high percentages of oxygen. We evaluated radiographic evidence of bronchopulmonary dysplasia (BPD) in survivors, who presented with respiratory distress within 6 hours after birth, by a radiographic scoring system measuring the severity of BPD by the Toce score and the degree of pulmonary hypoplasia by the Touloukian score. Fifteen of 45 survivors (33 percent) had clinical and radiological lung disease resembling BPD. As a group they had significantly higher Touloukian and Toce scores than survivors without BPD. Morbidity expressed as the duration of artificial ventilation, supplemental oxygen, and hospital stay was much higher in the BPD group. The hypoplastic lung in infants with congenital diaphragmatic hernia appears to be as susceptible to barotrauma and pulmonary oxygen toxicity as the lungs of prematurely born infants. To what extent BPD occurring in congenital diaphragmatic hernia survivors might influence the future development of lung function is not yet known.