The success of modern perinatal management techniques has led to the recommendation of the regional organization of perinatal services. This report summarizes the evaluation of a national demonstration program of such regionalization that was funded by the Robert Wood Johnson Foundation (RWJF) in 1975. In both funded regions and comparison areas, the neonatal mortality rates decreased sharply over the decade of the 1970s. This decline was linked to shifts in the hospital of delivery that indicated antepartum risk identification and transfer of management of high-risk pregnancies to tertiary centers for delivery, a change in service pattern consistent with some aspects of regionalization. The centralization of high-risk deliveries appeared so widespread that the special effect of the RWJF program could not be detected. Surveys of surviving 1-year-old infants showed that the decrease in neonatal mortality was accompanied by a decrease in selected morbidity.