57 newborn infants delivered by planned, repeat cesarian section were studied to determine the role of surfactant in transient neonatal respiratory distress. 22.8% of the newborn infants studied had transient tachypnea of the newborn. The mean amniotic fluid lecithin-sphingomyelin ratio (L/S) was 2.8 in normal infants and 2.6 in infants with transient tachypnea. The mean gastric aspirate L/S at the time of delivery was 3.0 in the normal infants and 2.7 in infants with transient tachypnea. There were no statistically significant differences in either amniotic fluid L/S or gastric aspirate L/S. Based on these results we speculate that, despite altered lung mechanics in neonates with transient tachypnea, lung maturity as determined by L/S ratio does not differ from that of normal neonates.