Paralysis of the diaphragm in infants may produce severe respiratory difficulty because of the paradoxic motion of the affected diaphragm and shift of a mobile mediastinum to the contralateral side. Six infants with diaphragmatic paralysis and severe respiratory distress underwent plication of the diaphragm by a simple technique. Five of the six infants had significant improvement in respiratory effort and were ultimately weaned from ventilatory support. One patient with bilateral paralysis had only minimal improvement. Diaphragmatic function returned in two patients after plication. Plication of the diaphragm is a safe and useful procedure to improve ventilation in infants with a paralyzed diaphragm. Since this technique does not prevent return of diaphragmatic function, it should be employed prior to the development of sequelae of prolonged assisted ventilation and sooner if the phrenic nerve is permanently injured.