Abstract Chest films in 300 routine vaginal deliveries, 100 premature infants, 100 infants born by cesarean section, and 50 intubated infants were obtained within two hours after birth. The incidence of pneumothorax was 1.3% in routine vaginal deliveries, 1% in premature infants, 2% in cesarean sections, and 6% in intubated newborns. Pneumomediastinum was demonstrated in 2.3% of normal deUveries, 2% of premature infants, 1% of cesarean sections, and 8% of intubated neonates. Apparent predisposing or associated factors included intubation, congenital anomalies, and meconium-stained amniotic fluid. No significant correlation with prematurity, dysmaturity, small size for age, cesarean section, or hyaline membrane disease was found.