Thirty cases of early-onset congenital diaphragmatic hernia were admitted to National Taiwan University Hospital from 1976 to 1990. The mortality rate has increased in recent years, with an overall mortality rate of 26.7%. Low PH value of initial blood gas, early onset of symptoms at birth and total absence of hemidiaphragm were the three most poor prognostic factors (P less than 0.01). Preoperative stabilization of those patients with an initial PH value less than 7.2 may be helpful (P less than 0.04).