The aim of the intensive care of the injured is the coupling of the availability and the requirement of the cerebral metabolic substates. The measurement of the cerebral blood flow is not currently available at the bedside and less direct monitoring is required. The cerebral perfusion can be estimated looking at the cerebral perfusion pressure (CPP), that can be easily measured using intracranial pressure (ICP) and the systemic arterial pressure (MAP) monitoring. Hundred-twenty-one consecutive head injured admitted to an Intensive Care Unit were studied assessing the severity of the neurological injury, the CT-Scan diagnosis of the intracranial lesion, the Trauma Score and the behavior of the ICP and MAP. The outcome was classified according to a modified version of the Glasgow Outcome Scale. More than 77% of the patients suffered raised intracranial pressure above 20 mmHg and 16 of them had a CPP less than 60 mmHg for more than 5 minutes. The outcome was directly related to the degree of intracranial hypertension and to the severity of insufficient CPP. The treatment of the severe head injured must be aimed at maintaining a good CPP, because of the close relationships between this value and the prognostic result. The monitoring of the ICP is a reliable and relatively safe procedure in this series, where the rate of infections complicating the intracranial recording is less than 3%.