Acute dizziness (including vertigo) is a common reason to visit the emergency room, and imaging with head CT is often performed initially to exclude a central cause. In this study, consecutive patients presenting with dizziness and undergoing head CT were retrospectively reviewed to determine diagnostic yield. Four hundred forty-eight consecutive head CTs in a representative sample of dizzy emergency room (ER) patients, including patients with other neurological symptoms, were reviewed to identify an acute or subacute cause for acute dizziness along with the frequency and modalities used in follow-up imaging. The diagnostic yield for head CT ordered in the ER for acute dizziness is low (2.2 %; 1.6 % for emergent findings), but MRI changes the diagnosis up to 16 % of the time, acutely in 8 % of cases. Consistent with the American College of Radiology appropriateness criteria and the literature, this study suggests a low diagnostic yield for CT in the evaluation of acute dizziness but an important role for MRI in appropriately selected cases.