The effectiveness of long term EEG monitoring in the localization of the epileptic focus was studied in 37 patients with temporal lobe epilepsy comprising 190 recorded seizures, in 19 frontal lobe epileptic patients with 172 recorded seizures and in 12 additional patients which were classified as fronto-temporal. In the temporal lobe group, 49/190 seizures began focally (26%) and 20/190 seizures exhibited a regional onset (10%). In the frontal lobe group, only 21 out of 172 seizures (12%) had a focal ictal onset. 41/172 seizures began regionally (24%). In the fronto-temporal group, 31/55 seizures disclosed a focal EEG onset (57%). This study demonstrates that there is a two-fold increase in seizures beginning focally in the temporal lobe epilepsy group versus the frontal lobe group.