Background: A neonate undergoes major physiologic changes during transition from intrauterine to extrauterine period. The percentage saturation of hemoglobin takes about 10 minutes to reach a level of more than 90%. This fact is to be borne in mind while resuscitating a newborn with oxygen to avoid its toxicity. It is still unclear whether the oxygen saturation profile could be affected by racial/ethnic variation, birth weight, sex, APGAR score or maternal factors (age, hemoglobin, type of labor) in term healthy babies. This study aimed: 1) To note the time taken for SpO 2 to reach a value of 90%; 2) To note the time taken for preductal and post ductal SpO 2 to equalize; 3) To look for the association between SpO 2 and various infant and maternal factors. Methods: Two hundred and seventy eight full term neonates born by normal vaginal delivery were included in this study. After birth, sensors were placed simultaneously on the pre (right hand) and the post ductal site (either foot) of the neonate. The SpO 2 readings were recorded at 1, 3, 5, 7 and 10 minutes after birth and every 5 minutes thereafter till readings from both these sites crossed 90% and equalized. Results: The mean (SD) time taken for the preductal and postductal saturation to reach 90% was 7.4 minutes (4.5) and 9.5 minutes (5.36) respectively. The mean (S.D) time taken for equalization of preductal and post ductal saturation was 11.46 (6.27) minutes. No statistically significant correlation was seen between the time taken for equalization of preductal and postductal SpO 2 and for it to reach 90% and factors such as maternal age, hemoglobin, type of labor, birth weight and sex of the baby. Conclusion: SpO 2 at 10 minutes reaches a value of > 90% in most of the healthy term neonates born through vaginal delivery, and these values had no statistically significant correlation with the neonatal or maternal factors. doi: http://dx.doi.org/10.4021/ijcp100e