The purpose of this prospective study is to show a technique for recording electroencephalographic activity via an endovascular approach in presurgical evaluation of epileptic patients. Technical aspects and insertion strategy are outlined. Advantages of intra-arterial electroencephalography have been demonstrated. It is a semi-invasive procedure that provides information in temporal lobe and extratemporal epilepsy. It allows a dynamic electroencephalographic recording and patient tolerance is excellent. Risks are practically absent. Disadvantages are: in comparison to ovale electrodes, chronic and multicontact recording is not possible and the recording is only intercritical.