AIM This pilot study evaluated changes in regional cerebral oxygen saturation and cerebral blood flow volume during the transitional period in healthy term and moderately preterm infants. METHODS The cohort comprised 16 preterm infants and seven full-term infants with mean gestational ages of 34 and 39 weeks, respectively. Longitudinal measurements were conducted during the first three days after birth. Regional cerebral oxygen saturation was determined bilaterally by frequency domain near-infrared spectroscopy. Flow volumes were determined in internal carotid and vertebral arteries by multiplying the time-averaged velocity by the cross-sectional area: cerebral blood flow volume was calculated as the sum of flow volumes and adjusted for brain weight. RESULTS Brain weight-adjusted cerebral blood flow volumes and regional cerebral oxygen saturation were similar in preterm and term infants. Regional cerebral oxygen saturation did not correlate with brain weight-adjusted cerebral blood flow volume. Right and left brain weight-adjusted internal carotid flow volumes did not correlate with right and left regional cerebral oxygen saturation. CONCLUSION Our findings suggest that during the first three days after birth there was adequate cardiorespiratory adaptation, cerebral perfusion and adequate compensation through the arterial circle of Willis in both healthy term and moderately preterm infants.