BACKGROUND Temporal lobe epilepsy is the most frequent of the epilepsies related with localization and one of the most refractory to pharmacological treatment. Temporal lobectomy curbs seizures in many of these patients, which improves their quality of life. METHODS Patient aged 45 who, during early infancy, started to suffer simple partial seizures that later went on to become generalised. These were well under control by adolescence but at 23 they became complex partial seizures that were resistant to different antiepileptic drugs. The patient was submitted to a complete presurgical evaluation and a left anterior temporal lobectomy was performed at the age of 44. After surgery he evolved favourably. The final diagnosis was that he was suffering from mesial temporal sclerosis, associated with a subcortical neuronal heterotopy of the parahippocampal region. We discuss the semiology and the aetiology with regard to this patient and in a general sense, and we also define the foundations upholding the decision to perform surgery, the areas that make up the epileptogenic zone, and the neurophysiological and neuropsychological tests, and the structural and functional neuroimaging that are used to measure those areas. Likewise, the different techniques that can be used in resection of the temporal lobe are analysed. We also set out an etiopathogenic hypothesis according to the histopathological results and comment on a number of related general aspects. CONCLUSIONS Progress in physiopathological knowledge, the development of diagnostic and surgical techniques, and its high efficiency and low morbidity have consolidated temporal lobectomy as a radical form of treatment for temporal lobe epilepsy that should be performed as early as possible once resistance to medication has been observed.