Follow-up data of 2 to 49 years' duration are presented on 257 patients with cortical excisions for non-tumoral frontal lobe epilepsy. Twenty-six percent have become and remained seizure free. Another 30% have had a marked reduction of seizure tendency. Thus a total of 56% have had a long term complete or marked reduction of seizure tendency after the cortical resection. The cortical resections were classified into 5 regional categories. Forty-seven percent of patients with anterior frontal resections were in the seizure free category, as were 35% of patients with excisions limited to the convexity cortex and 32% of patients with maximal or near maximal frontal lobectomy. Only 18% of patients with frontal parasaggital excisions were in the seizure free category, and 10% of the patients who had excision of frontal cortex plus limited excision of adjacent central and/or temporal cortex.