This survey covers 74 patients with temporal lobe epilepsy, resistant to medication, who underwent unilateral temporal lobectomy during the years 1960-1969 at Rigshospitalet, Copenhagen. Preoperatively all patients were socially incapacitated. In all patients a unilateral or predominantly unilateral temporal EEG focus was found. No tumour or gross vascular malformation had been recognized before or during operation. At follow-up 45 patients were free from seizures. A further 15 had obtained a reduction in their seizure frequencies by at least 75%, while the remaining 10 survivors, only obtained a slight improvement or remained unchanged. There were four deaths. The operation also favourably influenced the psychiatric status, which was found closely related to relief from seizures. Prognostically favourable factors were: i) preoperative presence of a single type of seizure, ii) duration of epilepsy of less than four years, iii) operation in or before early adulthood, iv) an anterior temporal or sphenoidal electrode focus, or both, on the EEG. The prognostically unfavourable factors regarding complete relief from seizures were: i) preoperative presence of grand mal, ii) age at onset of epilepsy or of the first grand mal seizure between 5 and 19 years of age, iii) preoperative duration of epilepsy of over ten years and of grand mal of over one year. Prognostically unfavourable factors regarding psychiatric normalization were: i) preoperative presence of psychosis, ii) ictal-affective attacks or automatisms of a complex nature, iii) impairment of intellectual functions. The eventual neuropathological conclusion was that the more specific and circumscribed the histological abnormality the better the final outcome. The social rehabilitation was found to be significantly improved by operation at an early age.