The case of a 2-month-old girl with congenital bilateral eventration of the diaphragm is reported. After normal delivery from cephalic position, the patient developed respiratory distress. Mechanical ventilation started immediately but extubation was difficult. A membranous lesion was found on computed tomography of the chest. Resection of the membrane between the right middle and lower lobes and bilateral diaphragmatic plication was performed. Histologically the membrane was a chest wall hamartoma. The patient was extubated on 6 day postoperatively and is alive and well 4 months after surgery.