A case of an empyema of cavum septi pellucidi and cavum Vergae is reported. A 60-year-old male was admitted because of fever, chill shivering, and slight conscious disturbance four days after head trauma. CT scan on admission showed cavum septi pellucidi and cavum Vergae. Lumbar puncture revealed whitish cloudy CSF containing 12256/3 WBC. So he was treated with antibiotics under the diagnosis of suppurative meningitis. Five days after administration of antibiotics high fever went down and consciousness was cleared. But about 10 days later his conscious level was lowered again. The follow up CT demonstrated remarkable expansion of cavum septi pellucidi and cavum Vergae with enhanced cavity wall. Empyema of the cavums was suspected and stereotaxic operation was performed. 10 ml of yellowish pus was aspirated. Post operative course was uneventful. CT scan of 15 days after operation revealed a marked decrease in size of the cavums, which almost completely disappeared three months later. Case similar to this was not found to be reported. The mechanism of formation of empyema of cavum septi pellucidi and cavum Vergae after meningitis in this case is discussed.