Ten new cases of peripheral osteoma of the mandible are described. These lesions are uncommon and only 15 other cases have been reported in the English language literature over the past 30 years. There is evidence to suggest that the peripheral osteoma of the mandible is a traumatically induced reactive lesion and that muscle traction plays a role in its initiation. In view of this possibility, the term "parosteal osseous hyperplasia" may be more appropriate for those lesions in which a positive history of trauma preceded the onset.