Between 1983 and 1987, 19 patients presenting with encephalic involvement of AIDS had an EEG recording during the early neurological examination. In 8 patients, EEGs were repeated 1 to 11 times during the course of the disease. All recordings were abnormal. A good EEG correlation existed with clinical, virological and bacteriological (SF), radiological, and histological data (10 cases). EEG recordings are useful to study the encephalic pathology of AIDS, not only for its secondary, but even more for its primary involvement.