The management of cerebral perfusion pressure is among the most controversial treatment issues. Cerebral perfusion pressure (CPP) is normally expressed as the difference between mean arterial blood pressure and intracranial pressure and has two important physiological roles in the patient with severe head injury. First, CPP represents the pressure gradient acting across the cerebrovascular bed and hence is an important factor in the regulation of cerebral blood flow. Second, CPP contributes to the hydrostatic pressure within the intracerebral vessels, and therefore is one of the factors that determines edema formation in the injured brain. The border between adequate and inadequate CPP should be assessed individually and continuously, as it may fluctuate in time. The treatment plan that includes rapid identification of intracranial hemorrhage, rapid evacuation of extra-axial blood, treatment of intracranial hypertension, and promotion of cerebral and systemic perfusion is likely to provide the best outcome for all patients.