From 1962 to 1988, 147 neonates were admitted for operative repair of CDH to the Division of Pediatric Surgery in the Children's Hospital of Cologne. Follow-up studies were performed on 45 patients ages 1 to 25 years representing 54.2% of the 83 survivors. 18 patients (40%) were entirely without any complaints, 11 patients (24.4%) had increased rates of respiratory infections. Especially in early childhood they suffered from obstructive alterations in the respiratory tract. No restrictive pulmonary changes were observed. Scintigraphic ventilation tests were performed on 44 cases. 34 (77%) tests indicated absolutely normal results. Some rare local deficits of lung ventilation were based on adhesive anatomic alterations of the thoracic skeleton and the diaphragm. The lung function tests conducted in 29 persons ages 6 to 25 years revealed that the vital capacity and the forced expiratory volume were all normal. We found an increase of the intrathoracic gas volume in 11 infants (disposition to pulmonary inflation). In 9 cases we observed a decrease in the mid expiratory flow curves and in 6 patients we measured an increase in the specific resistance of airways (tendency towards obstructive airway alterations). Nevertheless even former hypoplastic lungs revealed a good extensibility.