BACKGROUND: Measurement of mean arterial blood pressure (MABP) is feasible during neonatal transition. OBJECTIVE: The objective of this study was to investigate a potential influence of MABP on the cerebral regional oxygen saturation (crSO2) in preterm and term infants during the immediate neonatal transition. MATERIALS AND METHODS: Preterm and term infants were included in this observational study. The crSO2 was measured by near-infrared spectroscopy with the INVOS 5100C (Somanetics Corp., Troy, MI, USA) during the immediate neonatal transition (15 min after birth). The near-infrared spectroscopy sensor was applied to the left forehead. Furthermore, a pulse oximeter was applied to monitor arterial oxygen saturation (SpO2) and heart rate (HR). Fifteen minutes after birth, blood pressure was measured noninvasively at the left upper arm. Cerebral fraction tissue oxygen extraction (cFTOE) was calculated from SpO2 and crSO2. To investigate a potential association between crSO2/cFTOE and MABP, we performed a correlation analysis. RESULTS: A total of 462 preterm and term infants (186/292) were included. Mean gestational age was 31.0 ± 3.5 weeks for preterm infants and 38.9 ± 0.8 weeks for full term infants. Mean birth weight was 1.591 ± 630 g in preterm infants and 3.331 ± 461 g in term infants. There was a significant negative correlation between MABP and cFTOE (ρ = -0.19, p = 0.03) in preterm infants but not in term infants (ρ = 0.05, p = 0.39). There was no significant correlation between MABP and crSO2 in either group. CONCLUSION: MABP has an impact on cerebral oxygenation in preterm infants. Therefore, blood pressure monitoring during the immediate neonatal transition might be relevant for improving cerebral oxygenation especially in preterm infants.