• We report our observations from Intensive intracranial pressure (ICP) monitoring and serial clinical neurologic and electroencephalographic examinations in ten asphyxiated full-term neonates, of whom five died and at least two survivors had multiple severe neurologic handicaps. Direct measurements of ICP were obtained by a newly developed infant subarachnoid bolt and/or a transfontanelle pressure transducer. Simultaneous ICPs were recorded and correlated when possible. We noted a dependence of transfontanelle ICP values on application technique and force. In infants with no bleeding diathesis, the subarachnoid bolt was safe and no complications were encountered. Only six infants experienced pathologic elevations of ICP following birth asphyxia, and of these infants only two had sustained, marked Increases of ICP. We also noted abundant fluctuations of cerebral perfusion pressure (mean arterial blood pressure minus ICP), but the majority of fluctuations were accounted for by mean arterial pressure changes rather than ICP changes. We found no deterioration of clinical neurologic function as measured by serial mental status examinations and electroencephalogram samples at the time the maximum ICP was measured. We also noted very little change in ICP during most electrographic seizures. In these infants ICP did increase after birth but major ICP elevations were uncommon and did not appear to introduce any acute functional neurologic disturbances. Most changes in cerebral perfusion pressure were attributed to blood pressure rather than ICP changes. It appears unlikely that cerebral edema and elevated ICP play a major role in determining neurologic outcome in some asphyxiated term infants.