While structure of the central nervous system (CNS) is evaluated through diagnostic tests such as computed tomography or magnetic resonance imaging, CNS function requires special monitoring techniques. These techniques are particularly useful adjuncts to the clinical examination, especially in the critically ill patient. Monitoring techniques include intracranial pressure monitoring, cerebral blood flow monitoring, cerebral hemodynamic assessment, and electrophysiologic monitoring. Rationale and specific applications are unique to each technique. Nursing considerations focus on knowledge of rationale for monitoring, providing safe patient care, validating appropriateness of interventions based on monitoring, and investigating the relationship of monitoring to outcome.