Cerebral hypoxia-ischaemia occurring in the fetus and newborn is a major cause of acute mortality and chronic neurologic disability in survivors. Statistics suggest an incidence of systemic asphyxia in 1-2/1000 full-term infants and an incidence that approaches 60% in very low birth-weight newborns. Although the neuropathological features are not exclusively characteristic of full-term or preterm babies, it is well known that the gray matter is predominantly involved in the term baby while the white matter is damaged in the preterm newborn. In the premature infant encephalopathy is often accompanied by peri-intraventricular haemorrhage. The different distribution of neuropathologic lesions arising from perinatal hypoxia-ischaemia depend on several factors such as intrinsic cellular and regional vulnerability, vascular factors, nature and duration of the insult, age and maturity of the infant.