Neurological examination of the comatose patient can be particularly challenging because the patient cannot follow commands. Patients in a comatose state can have either a structural or a metabolic derangement. The goal of the exam of the comatose patient is to determine the likely cause of the coma. This chapter describes coma and examination strategies specific to comatose patient. It discusses coma mimics and differentiates between true comatose state. The term coma describes a pathologic state of unarousable unresponsiveness. The person is unable to be aroused and is unaware of their surroundings or condition. Comatose patients do not make any purposeful responses or movements. Arousal is dependent upon an intact ascending reticular activating system in brainstem. Awareness typically resides in the cerebral cortices. The evaluation of coma includes many different components, including physical examination, neurological examination, laboratory findings, neuroimaging, and additional diagnostic studies.