Stroke is the third most common cause of death, and being among the most common causes of severe disability in adults of developed countries accounts for a large proportion of health care costs. Its impact on individual patients, their families and society as a whole is immense. Approximately 200 per 100000 adults per year will have their first stroke. Because the incidence of stroke increases with age, the absolute number of patients with stroke is likely to increase even more, given that the population of aged adults is also increasing. However, brain injury from ischemia does not affect only the adult population. It is a major cause of mortality and severe neurodevelopmental disability (cerebral palsy, mental retardation, epilepsy and learning disabilities) in the pediatric – especially the newborn – population. The drain on resources to support such children (often long into adulthood or an entire lifetime) is also quite significant. Although the etiologies for ischemic brain injury in adults and children may differ, much of the pathophysiology underlying neural cell death and dysfunction is quite similar. In the case of newborn infants, despite advances in technology allowing better obstetric and neonatal care and a deeper understanding of the pathophysiology of perinatal asphyxia, the incidence of hypoxic–ischemic encephalopathy (HIE) in neonates has remained essentially unchanged over the last few decades.