Background:The objective of this study was to review infants with congenital diaphragmatic hernia (CDH) from the clinical and surgical aspects, and to analyze the risk factors affecting the outcome. Patients and Methods: The records of 33 infants with CDH who were admitted to the Neonatal Intensive Care Unit (NICU) from January 1989 to July 1996 were retrospectively reviewed. The mean gestational age was 38.87±2.6 weeks and the mean birth weight was 2896±700 g. The male to female ratio was 2:1. Twenty-six infants had leftsided and seven had right-sided CDH. All infants required mechanical ventilation within six hours of being born. Results: Nineteen infants survived until hospital discharge and 14 infants died, giving an overall mortality rate of 43%. We noted that pH of less than 7.3, PaCO2 of more than 45 mm Hg, or peak inspiratory pressure of more than 25 cm, were associated with high mortality. A higher risk of mortality was also seen in infants with persistent pulmonary hypertension of the newborn (PPHN). Survival rate was observed to be slightly higher in infants who had surgical repair beyond 48 hours of age. Survivors and nonsurvivors were comparable in terms of a 5-minute Apgar score, sex, mode of delivery, PaCO2 at presentation, the site of diaphragmatic defect, air leak syndrome, associated congenital heart disease, and the presence of stomach or viscera in the thorax. Conclusion: High ventilatory support and moderate-to-severe respiratory acidosis at presentation and PPHN during hospital course were found to be associated with high mortality. Ann Saudi Med 1999;19(6):501-504.