We retrospectively reviewed the treatment protocol and outcome of patients delivered at our institution with prenatal diagnosis of congenital diaphragmatic hernia (CDH) from 1988 to 1997. Patients were divided into four chronological groups according to the change of treatment protocol. Group 1: 5 patients born from July 1988 through December 1990, a period when CDH was considered to be a surgical emergency, underwent immediate repair of hernia after birth. Group 2: 6 patients born from 1991 through June 1993 were treated using a management protocol of delayed repair after stabilization except when their postductal PaO₂ exceeded 200mmHg. Group 3: 6 patients born from July 1993 through December 1995 were treated with the same protocol as group 2, but nitric oxide inhalation was available. Group 4: 7 patients (1996-1997) underwent early repair of hernia with the aid of inhaled nitric oxide. All the patients but one were delivered by cesarean section. There were no statistical differences in gestational age, birth weight, umbilical arterial blood gases, Apgar scores, hernia side, or herniated viscera among groups. The survival rate was 60% in group 1, 17% in group 2, 33% in group 3 and 100% in group 4, (P<0.05). Two patients each in groups 2 and 3 died during stabilization without undergoing surgical repair. Extracorporeal membrane oxygenation (ECMO) was instituted in 2 patients in group 1, 4 in group 2, 3 in group 3 and none in group 4. Out of 9 patients treated with ECMO, 8 died. Inhaled nitric oxide was applied to 6 patients in group 3 and 5 patients in group 4. Delayed operation after stabilization did not yield a good outcome. Inhaled nitric oxide may be useful in the treatment of CDH.