Dizziness or vertigo is frequently caused by a disorder of the vestibular system. The central vestibular system includes the vestibular nuclei and their central nervous system (CNS) connections. A carefully obtained history is critical in the evaluation of a patient's complaint of dizziness or vertigo. This is important diagnostically because vertigo usually results from vestibular system disorders, whereas nonvertiginous dizziness usually results from nonvestibular system disorders. The differential diagnosis of dizziness or vertigo can be approached by determining whether the disorder is due to an abnormality of the vestibular system or of nonvestibular systems. Imaging studies of the skull and brain may be indicated in the evaluation of a patient with dizziness or vertigo. A patient who presents to the emergency department (ED) acutely ill with vertigo accompanied by severe nausea and vomiting requires immediate stabilization. Benzodiazepines can be used acutely to treat moderately severe anxiety syndromes that cause dizziness.