Vascular development was studied by means of immunohistochemistry, using a vascular endothelial growth factor (VEGF) antibody in human normal and periventricular leukomalacia brains. In the cerebral cortex, VEGF was expressed transiently in the endothelial cells of vessels in the leptomeninges, cortex, deep white matter, subependymal germinal layer, ependymal cells facing the lateral ventricles, and choroid plexus epithelia. In the leptomeninges, VEGF was expressed from 20 to 40 weeks gestation. In the cerebral cortex and deep white matter, VEGF was expressed from 17 weeks gestation, increased with maturation, was highest between 24 and 28 weeks gestation, and decreased gradually thereafter. In the subependymal germinal layer, VEGF was expressed the earliest at 9 weeks gestation, increased with maturation, was highest between 20 and 24 weeks gestation, and then decreased. In the ependymal cells and choroid plexus epithelia, VEGF was expressed between 22 and 40 weeks gestation and between 9 and 37 weeks gestation, respectively. VEGF may be transiently expressed in the vessels in the fetal and neonate periods in connection with vascular maturation and proliferation. In periventricular leukomalacia brains, VEGF was expressed in both astrocytes and endothelial cells in vessels that comprised neovascularization around foci of necrosis. VEGF plays important roles in embryonic angiogenesis and neovascularization around foci of necrosis.