The effect of bilateral frontal leukotomy on motor function was evaluated by neurologic examination, tests of praxis, and appropriate neuropsychologic tests administered to five groups of subjects. Postleukotomy schizophrenic patients were subdivided into three degrees of recovery. Two nonleukotomized groups served as controls for effects of schizophrenia, age, and education. The results indicate that the size of the bifrontal damage was not significant in the response to the motor tests, whereas the severity of schizophrenia clearly affected results. As tested, bilateral orbitofrontal white matter lesions did not disturb motor competency.