To investigate the brain function of elderly schizophrenic patients, quantitative EEGs of such patients were compared with those of healthy elderly controls. In schizophrenics, increases in delta and slow theta (4.0-6.0 Hz) waves were thought to be due to the influence of antipsychotics. Characteristic EEG features of these patients included the following: 1) more fast theta (6.0-8.0 Hz) wave was observed, with less alpha wave faster than 9.0 Hz, 2) the reduction in alpha 3 (10.0-11.0 Hz) wave was limited to the frontal regions. The present EEG findings are thought to characterize the traits of the subtype of chronic severe schizophrenia. The reduction in alpha 3 wave in the frontal regions may be one expression of the hypofrontality of schizophrenia.