Background: The impact of arterial blood pressure on cerebral oxygenation during immediate postnatal transition is poorly understood.Purpose: Here we investigated the association between arterial blood pressure (BP), cerebral tissue oxygenation index (cTOI), and cerebral fractional tissue oxygen extraction (cFTOE) during the immediate postnatal transition in preterm and full-term neonates. Methods: This prospective observational study included preterm and term neonates who did versus did not require respiratory support. Oscillometric BP was measured at 5, 10, and 15 minutes after birth. cTOI was continuously monitored using near-infrared spectroscopy, while arterial oxygen saturation (SpO2) was recorded using pulse oximetry. cFTOE was calculated from cTOI and SpO. cTOI and cFTOE values were correlated with systolic blood pressure (SBP), diastolic blood pressure (DBP), and mean arterial pressure (MAP) at all time points. Correlation and mixed-model analyses were then performed. Results: A total of 102 neonates were enrolled: 51 preterm (33 with, 18 without respiratory support) and 51 term (14 with, 37 without respiratory support). In preterm neonates requiring respiratory support, cTOI was positively correlated with DABP at all time points and with MABP at 15 minutes. cFTOE was negatively correlated with MABP and DABP throughout the experiment and with SABP at 5 minutes. No significant correlations were observedamong the other groups. A mixed-model analysis showed that MABP and DABP were significantly associated with cFTOE but not cTOI independent of gestational age or respiratory support. Conclusion Among preterm neonates requiring respiratory support, cTOI and cFTOE were associated with arterial BP during the immediate neonatal transition. Only cFTOE showed a slight association with BP among stable preterm and full-term neonates. These findings suggest impaired cerebral autoregulation in compromised preterm infants during the immediate postnatal transition.