Patients with medically refractory epilepsy when referred for surgical treatment often undergo extensive investigations to determine whether surgical treatment is feasible. Surgical feasibility is determined by identifying the location and number of seizure foci and their relationship to eloquent areas of the brain. Good surgical outcome depends on complete resection of seizure foci without any damage to eloquent brain function. Various noninvasive and invasive techniques are used in the presurgical evaluation of patients with epilepsy that include imaging techniques, electrophysiologic studies, and tests to determine functional areas. Understanding of the principles of seizure localization and of the effects of anesthetic drugs on the various preoperative investigations is essential for patient management. In this review article, we discuss the role of the anesthesiologist in patient management during many of these investigations and the role of anesthetic drugs to aid in the localization of the seizure focus and of determining eloquent brain function.