It is now feasible and desirable to continuously monitor brain function with EEG in critically ill patients. Nonconvulsive seizures are more common than previously recognized and may contribute to impaired mental status and brain injury. Alerting stimuli commonly elicit periodic or ictal-appearing EEG patterns. Cerebral ischemia can be detected at a reversible stage with continuous EEG monitoring (cEEG). With the current availability of treatments for acute ischemia, this early detection has great potential for the prevention of stroke, but is only now beginning to be utilized for this purpose. The intensive care unit poses many technical difficulties for EEG acquisition, and artifact recognition is more important than ever. Recording synchronized video with EEG is essential for maximizing the efficiency and accuracy of cEEG interpretation, and quantitative EEG analysis can be quite helpful. The role of the EEG technologist is particularly important in these patients to aid in recognizing and minimizing artifact, to enhance communication between electroencephalographers and clinicians, to assess the effect of alerting stimuli, and to note possible subtle clinical correlates of electrographic seizures.