Early newborn age is a crucial phase of brain development, which can be characterized by in-vivo measurement of cerebral blood flow (CBF). In this study we assessed regional CBF in very preterm infants longitudinally during the ex-utero third trimester using arterial spin labeling. CBF in preterm infants significantly increased with postmenstrual age in all regions with the most rapid increase and the highest mean of CBF in the cerebellum. Lower CBF was associated with intraventricular hemorrhage and patent ductus arteriosus. CBF in preterm infants was higher than that of healthy full-term controls at term equivalent age.