Anomalies of the diaphragm, particularly eventration, are not encountered frequently in clinical practices. Diaphragmatic eventration is generally accepted as an anomaly high position of part or all of the diaphragm, usually associated with a marked decrease in muscle fibers and a membranous appearance of the abnormal area. We experienced 3 cases of the congenital diaphragmatic eventration at the department of the thoracic and cardiovascular surgery, Maryknoll Hospital, which were treated successfully.