Glucose, an essential substrate for brain oxidative metabolism, is transported across the adult blood-brain barrier by Glut 1, a facilitative glucose transporter. Employing postmortem human brain samples and Western blot analysis, we demonstrated the presence of a 47-55 kilodalton Glut 1 protein in preterm and term newborn. The level of Glut 1 in both the preterm (24-33 weeks; n = 12) and term (38-40 weeks; n = 4) neonates was comparable to that of the adult (n = 5). Using paraffin brain sections and immunohistochemical analysis, in the preterm (24-25 weeks) and term (40 weeks) infant, similar to the adult we demonstrated the presence of Glut 1 in microvascular endothelial cells which constitute blood-brain barrier forming cells. The ontogenic conservation of the blood-brain barrier Glut 1 make detecting defective glucose transport across the neonatal blood-brain barrier feasible. Genetic or acquired defects in Glut 1 can impede the transport of glucose across the blood-brain barrier, thereby, resulting in irreversible neurological compromise during infancy. Earlier detection during the neonatal period, and appropriate intervention, may set the stage for altering the outcome of affected infants.