Etiological manifestion of unilateral a bilateral hypertrophy of masseter muscle, is not cleanly defined. It thought to have a congenital combined with occlusion, psychogenic & neurophysiologic rances. The disease is cleanly differentiated from other disease, however careful distinction of the parotid disease is necessary due to its location. The patients mainly complaint aesthetic problems, surgical excision is the treatment of choice. Although no recurrence cases were reported, follow up for this is recommended.