Critical illness is associated with multiple system organ dysfunction, and neurologic dysfunction is increasingly assessed and recognized. Neurologic dysfunction includes encephalopathy, cognitive, neuromuscular and psychiatric impairments, all of which can be severe and are associated with significant morbidity. Medical technological advances have improved central nervous system monitoring in critically ill patients, allowing quick and reliable diagnosis neurologic dysfunction such as delirium, sensory processing deficits, seizures, and encephalopathy to name a few. A number of neurologic evaluation tools are available to assess the neurologic status of critically ill patients both acutely, as well as longterm. Each tool provides unique information regarding neurologic status and has associated strengths and weakness. Identification of neurologic dysfunction allows for the development of working plans for prognostication, therapeutics, and rehabilitation that address the needs of each ICU survivor. This review focuses on the evaluation of neurologic sequelae during critical illness and long-term neurologic outcomes in survivors of critical illness.