The authors report a case of a young man, 18 years old, with left hemiplegia, epilepsy and psychic troubles, since he was 4 years old, with unilateral right lesions in the EEG and PEG; the EEG showed spreaded changes in the left cerebral hemisphere. A right cerebral hemispherectomy was performed, with excision of the anterior third of the caudatus nucleus and all the amygdaloid nucleus. Postoperatively there was meningitis and osteomyelitis, treated by antibiotics and surgery. In spite of this a striking improvement was obtained, for the patient was freed from convulsions, his behavior (sociability, cooperation) became much better and even spasticity in the left inferior limb lessened. No improvement in the productiveness of the intellectual work was noticed. Walking was possible. Protopathic sensibility was normal in the hemiplegic side and as for the epicritic one even if diminished, it was not totally absent, being practically the same as before the operation. Visual fields showed left homonimous hemianopsia. The good results reported by others in infantile hemiplegia treated by cerebral hemispherectomy were confirmed.