Term neonates (N = 35) with an one minute Apgar score of greater than or equal to 8 and mean umbilical artery pH values within normal were monitored by pulse oximetry. SaO2 monitoring started one minute after delivery. The initial SaO2 ranged from 40 to 75%. Neonates with a SaO2 above 80% five minutes after delivery remained untreated, neonates with a SaO2 below 80% received mask CPAP (figure 1). The initial difference in SaO2 between the groups was statistically significant (p less than 0.05). Mean umbilical artery pH and one, five and ten minutes Apgar score values were statistically not significant between the groups (p greater than 0.05). CPAP had been terminated as soon as SaO2 had reached 90%. This had been the lowest value monitored in spontaneously breathing neonates one day after delivery. Our findings indicate that neonates may sustain prolonged periods of decreased SaO2 which had not been detected by umbilical artery pH nor by the Apgar score. SaO2 monitoring by pulse oximetry served as a valuable method in the immediate newborn evaluation.