An analysis of the long-term results of 42 patients with epilepsy and behavioural disturbances treated by stereotactic fornicotomy has been carried out. An attempt has been made to classify the indications for this surgical method. Patients must be selected according the following criteria: the lower age groups, severe behavioural disturbances and epileptic symptomatology unchanged by any other form of treatment, normal I,Q. and electroencephalographic demonstration of a temporal lobe epileptic focus. The stereotactic lesion of the fornix was always carried out homo-laterally and was without morbidity and mortality. The results have been satisfactory in 70% of our patients but mainly when aggression was the main feature. The best results are related to a high I.Q. and a short clinical history.