Using microangiography combined with benzidine stains, we studied the development of vessels in the meninges, cortex, and white matter in 30 neonates, 16 infants and children, and eight neonates with periventricular leukomalacia. The vessels of the deep white matter, especially the ventriculofugal arteries, are useful as an index of cerebrovascular maturity. The lesions of primary leukomalacia utilizing the combined radiographic-histological techniques are localized to the ends of ventriculofugal arteries or between medullary arteries. The infants with leukomalacia have either poorly developed vessels or severe clinical complications producing ischemia or both.