The authors have studied psychiatrically, pre and post-operatively, a series of 31 cases operated upon for temporal lobe epilepsy. They have concluded that medically uncontrollable limbic epilepsy is associated in its physiopathological substrate to: pathological irritability, affective tenacity, impulsiveness, epileptic cognitive dysfunction and abstraction deficiencies of intellectual process. The high incidence of these events in the patients studied demonstrate the existence of a causal relationship between these abnormalities and the limbic epilepsy. Unilateral temporal lobectomies have been demonstrated to be very efficient for the control of epileptic seizures, whose frequency was remarkably reduced post-operatively. The operation resulted in a major reduction of the psychiatric manifestations of pathological irritability, impulsiveness, epileptic cognitive dysfunction and the instability of abstraction capacity produced by affective impacts. Affective tenacity was ill affected by the surgical procedure, although a favourable effect was noticed. The presence of bilateral temporal foci did not decrease the efficacy of the surgical intervention, nor its effect on the seizures or the effect of surgery on the studied psychopathological changes.