Intraoperative neurophysiological monitoring (INM) is underutilized during the anteromesial temporal resection (AMTR) in epilepsy surgery. Herein we report a case with intraoperative capsular infarction which was early detected by INM. Among the modalities of INM, left motor evoked potentials (MEP) showed suddenly decreased amplitude of compound muscle action potentials, after the electrocoagulation in left mesial temporal areas. Postoperative neurologic and MRI findings were well correlated to the intraoperative MEP features. We also discuss the usefulness of INM during the AMTR.