&NA;A number of reliable methods are available for the short term monitoring of intracranial pressure (ICP). However, the danger of infection and the need for external connections make the use of these methods for extended periods inappropriate. Most previously described devices for chronic monitoring of ICP are of limited value because of uncertain drift from zeropoint readings. The Hittman‐Meyer ICP sensor approaches the ideal for a long term monitoring device. It is fully implantable and is accurate over a wide range of pressures and for extended periods. It is designed so that in vivo calibration may be performed in a noninvasive fashion. We report the use of this device in eight patients with pseudotumor cerebri. It has functioned accurately for periods ranging up to 14 months after implantation and has proven to be a valuable aid in the management of these patients. (Neurosurgery,5: 666‐670, 1979)