Objective To investigate whether the mode of delivery may affect neonatal cerebral haemodynamics during the first hour of life. Design Prospective study.Sample Healthy infants with gestational age ! 37 weeks and birthweight appropriate for gestational age, born after uncomplicated pregnancy by vaginal delivery or elective caesarean section, two to five hours after the delivery. Methods Near infra-red spectroscopy was used to measure changes of oxygenated haemoglobin, deoxygenated haemoglobin, oxidized-reduced cytochrome aa3, and mean cerebral oxygen saturation (mixed cerebral oxygen saturation ¼ oxygenated haemoglobin/total haemoglobin). Changes in cerebral blood volume were calculated. Results Near infra-red spectroscopy data did not show significant differences between infants born by vaginal delivery or by caesarean section. There was a significant decrease of oxygenated haemoglobin and change of cerebral blood volume values at 120 and 180 minutes in both the groups, while deoxygenated haemoglobin and oxidized-reduced cytochrome aa3 were unchanged. Conclusions A decrease of cerebral blood volume occurs after birth and this occurs both in infants born by vaginal delivery and by caesarean section.