Osteomas of the temporal bone are rare, especially osteomas originating from the mastoid process. Most often occur in women aged 20—30 years. The maximum growth rate is observed during puberty. Usually, the neoplasm becomes an accidental finding on X-rays or CT scans. The clinic of osteoma depends on its location and size. The patient may complain of a cosmetic defect, headache, discomfort and a feeling of heaviness in the area of the neoplasm. In this clinical case, a long-term asymptomatic course of osteoma of the temporal bone is described. CT examination was used for its visualization, and treatment was carried out surgically using a drill.