Since Legg,13in 1880, reported a tumor of ill defined outline involving the masseter and temporalis muscles in a 10-year-old girl, less than 40 cases of benign masseter hypertrophy have been described in the literature. However, the fact that the 3 cases discussed here came under our observation during a period of less than 7 months, together with Barton's2statement of having seen more than 30 cases within 10 years, indicates clearly a more frequent incidence of this condition. According to Caldwell,4the paucity of reports may be due to its comparatively small clinical importance, except in differential diagnosis and in instances where there is an indication for surgical correction for cosmetic reasons. Though the etiology of benign masseter hypertrophy has not been determined with finality, several theories of its origin have been advanced. Barton2describes two types which may be unilateral or bilateral. In the