This article reviews current and future applications of continuous electroencephalography (cEEG) to monitor brain function and physiology in the neurologic intensive care unit. In comatose patients, cEEG may provide otherwise unobtainable information and influence therapeutic management, and also help determine the prognosis of patients with acute brain injury. This technique is best used for the detection of subclinical seizures, which may frequently occur during or after treatment of convulsive status epilepticus and after many types of acute brain injury, particularly trauma. The other main application of cEEG is as a primary monitor of brain function. cEEG can detect focal cerebral ischemia, such as that caused by vasospasm after subarachnoid hemorrhage, as well as global ischemia related to intracranial pressure elevation and insufficient cerebral perfusion pressure. Other potential applications include prognostication in coma and titration of continuous infusion sedative therapy. New technologic developments include continuous digital video EEG, automated seizure-detection software, and user-friendly online quantitative EEG analysis.