Excluding lesions of the external auditory canal, osteomas of the mastoid bone are rare. Osteoma is benign, slow growing mature bone. Although most of these lesions produce no serious symptoms, they are of interest to the otolaryngologists since they may cause noticeable cosmetic alterations. Treatment is indicated for symptomatic osteoma. Recently, authors have experienced two cases of the osteomas which develop in the mastoid process of the temporal bone, so report with review of literature.