The physiopathology of intracranial pressure and its measuring techniques are briefly discussed. Such measurements may be achieved: 1) At lumbar level (measurement of cerebrospinal fluid): the main limitations of this method are due to impossibility of long term recording and the danger of "cerebral erniation* in patients with increased ICP. 2) At cranial level with: a) ventricular catheter connected to a pressure transducer: its limitations are due to difficulties in entering small and/or displaced ventricules in case of cerebral edema or expanding lesion, danger of infections, and catheter obstruction amongst others. b) pressure transducer in the extradural space connected with external recorder by electric wires: its limitations are due to frequent lack of parallelism with the dural surface and the variability of correlations between extra and intradural pressure; c) subdural pressure transducer; these appear the most reliable both from the literature and from the Authors personal experience. The Authors stress the importance of ICP monitoring in head injuries and after intracranial surgery (mostly for an early detection of complications due to cerebral edema or hemorrhages).