In Europe and America, acute mastoiditis usually appears as a complication of acute otitis media, and some patients develop subperiosteal mastoid abscesses. In Nigeria, however, most subperiosteal mastoid abscesses develop from chronic otitis media with cholesteatoma. Of the 16 patients with subperiosteal mastoid abscesses discussed, 11 (69%) had cholesteatoma and only five (31%) had granulation tissue in the mastoid cavity. The ideal treatment for these cases is modified radical mastoidectomy. Radiographic investigation of the mastoid can be useful in the diagnosis of cholesteatoma in the presence of a subperiosteal mastoid abscess.