The incidence of acute mastoiditis has decreased significantly because we can effectively treat otitis media with oral antibiotics. Inadequate or delayed treatment of otitis predisposes to the development of mastoiditis and more serious, life-threatening complications. Extension of the infectious process beyond the mastoid system can lead to a variety of intracranial and extracranial complications including meningitis, epidural and intracerebral abscesses, vascular thrombosis, osteomyelitis, and abscesses deep within the neck. Signs of clinical deterioration in a patient with otitis media should indicate to the general practitioner that a more serious condition is evolving and surgical intervention may be necessary. Computed tomography is considered the imaging modality of choice for patients with acute mastoiditis because it can define clearly the regional anatomy and provide important diagnostic information.