Histological studies were performed on the temporal bones of 17 persons who died of intracranial abscess as a complication of chronic otitis media and mastoiditis. In all cases the route of intracranial infection was via the dura mater rather than through the labyrinth. During the acute stage of intracranial abscess formation, the site of intracranial invasion showed a destructive inflammatory reaction characterized by the presence of granulations, resorption and sequestration of bone, invasive cholesteatoma, collections of purulent exudate, and necrosis of dura mater. At this stage any attempt at definitive removal of diseased tissue would necessarily result in a larger dural defect at a time when local disease and systemic illness present unsuitable conditions for reparative procedures. For this reason it would seem prudent to limit early otologic surgery to ensuring adequate drainage (e.g., postauricular open-wound drainage) and to perform corrective surgery (e.g., tympanomas-toidectomy with repair of the dural defect) after the intracranial abscess has been brought under control.