Electroencephalography (EEG) continues to be the most important diagnostic tool in the management of patients with epilepsy. In particular, the high specificity of interictal epileptiform discharges makes scalp EEG a valuable tool in the evaluation of patients with a history of seizures or seizure-like episodes. Advances in technology, most notably the development of digital video-EEG, have significantly expanded the utility of EEG. In addition to the routine EEG, long-term monitoring studies including video-EEG, ambulatory EEG, and continuous EEG monitoring play important roles in various aspects of the diagnosis and treatment of epilepsy. Recent developments in computerized seizure detection and prediction algorithms, particularly those utilizing intracranial EEG electrodes, hold promise for future development of novel treatment strategies.