To explore the long-term effects of bilateral prefrontal destruction, 16 schizophrenics who had undergone prefrontal leukotomy approximately 25 years earlier were studied by neurologic examination, psychiatric outcome, EEG, computerized tomography (CT), and a battery of neuropsychological tests. Five nonleukotomized chronic schizophrenics and five age-matched normal subjects served as controls. We report details on the subjects, outline the test procedures, and offer an overview of the long-term residua. In general, the larger the frontal lesion demonstrated by CT, particularly if asymmetric, the better the psychiatric outcome and the better the performance on psychological testing, but there was no correlation between frontal lesion size and either neurological or EEG abnormality.