Seventy-five patients with intracranial hypertension whose Glasgow Coma Score (GCS) was 8 or below and in whom intracranial pressure (ICP) was monitored were examined for complications of this procedure. In 20 of the 75 patients we used only an intraparenchymal fiberoptic ICP monitoring transducer, while, in the remaining 55 patients, who required CSF drainage, a ventricular drainage set (VDS) was used in addition to ICP monitoring. The duration of monitoring with the ICP transducer alone was approximately 5.1 +/- 2.6 das (min. 1, max. 13) and that of ICP monitoring with VDS was 6.2 +/- 3.1 days (min. 1, max. 13). In 8 cases a total of 9 complications were experienced (12 %). These complications were infection in 3 cases (4 %), epidural hematoma in 2 cases (2.7 %): disconnection in 2 cases (2.7 %) and contusion in 2 cases (2.7 %). Although none of the 44 patients who were monitored for less than 5 days experienced infection, 3 of the 31 patients monitored for longer than 5 days did experience infection (9.7 %) (p < 0.05). None of the 20 patients who underwent ICP monitoring only experienced infection. However, 3 of the 55 patients in whom the ventricular drainage set was implanted in addition to the transducer for ICP monitoring experienced infection (p < 0.05).