The outcome of term newborns with birth asphyxia and moderate to severe hypoxic ischemic encephalopathy remains very poor. After the primary phase of energy failure during asphyxia, neuronal cell metabolism may deteriorate in a secondary phase of brain injury. The window between these two phases opens the way to potential neuroprotective treatments such as brain cooling. Promising experimental data on controlled hypothermia need to be examined with clinical trials.