Treatment of postoperative pulmonary insufficiency in congenital diaphragmatic hernia has two aims: on the one hand, it serves to assist in achieving full pulmonary development, whereas on the other hand it aims at lowering pulmonary hypertension. Full development of the hypoplastic lung is the decisively important factor with regard to improving ventilation and perfusion. The same degree of importance is attached to correcting hypoxia as well as acidosis. The different performance of the lungs in respect of mechanics of breathing can be influenced most effectively by a well-balanced application of several measures exercising an influence on pulmonary pressure, such as positive ventilatory pressure and thoracic suction drainage. If these measures are unsuccessful and in case of a clinically relevant ductal right-left shunt, it is recommended to administer vasodilators; in exceptional cases, ductal ligature can be the procedure of choice. These therapeutic problems are discussed on the basis of an evaluation of the authors' own patients treated between 1976 and 1980 (10 cases).