CONGENITAL diaphragmatic hernia per se constitutes a threat to life in the newborn. If an operation is not performed, according to available statistics, most of these infants do not live beyond two months. The most serious of these defects is the complete absence of the hemidiaphragm. No report of an operative survival for the correction of this abnormality was found in a review of the American and British literature. It is the purpose of this paper to describe a new operative technique which has been successfully executed in man. Subsequent clinical experience and animal experiments make it appear that this is a reasonable approach to the problem. The technique involves the suture of the respective lobe of the liver to the endothoracic fascia to separate completely the thoracic and abdominal cavities. If it becomes necessary to resect a large portion of the diaphragm because of malignant growth, it is felt