We believe that monitoring of the ICP is an important facet of the intensive care management of children with diseases that affect the normal intracranial homeostatic mechanisms and in whom changes in intracranial compliance or ICP are likely to constitute part of their disease. For maximum benefit from monitoring the ICP, well-trained nurses and physicians who understand the basic physiology of the intracranial space and the limitations and uses of the pressure monitor are necessary. ICP measurements are no substitute for a careful neurologic examination but in comatose patients are a more reliable reflection of the pressure-related events occurring within the cranium. The single measure of ICP from the subarachnoid space in the lumbar area is quite unreliable. We have seen that in children the usual situation, even when compliance is low, is of a low-resting baseline ICP with pressure waves superimposed upon it. Thus, the resting ICP, the presence of pressure waves, the state of intracranial compliance, the response to therapy and the need for further therapy can only be accurately known if the ICP is continuously measured. The response to therapy may vary considerably at different times in the same patient, again emphasizing the need to know exactly what is happening. Extreme measures to control the ICP such as hyperventilation and muscle paralysis, hypothermia or barbiturates can only be used safely when the ICP and CPP are known. Using ICP monitoring as the guide to therapy, it has been possible to control the ICP and maintain it within normal limits in over 90% of our patients. Despite control of the ICP and the avoidance of secondary ischemic injury or cerebral herniation, death or incomplete recovery may still occur as a result of the primary disease process.