Eosinophilic granuloma of bone is a disease with an incidence of one new case per 350,000 to 2 million per year, which is an uncommon disease of maxillofacial region, and presents in more than 90% in children under the age of ten with predominance for males. As a result, eosinophilic granuloma of the jaw is always unconsidered in the differential diagnosis of similar lesions by many clinicians. It is difficult to make a correct diagnosis on it without proof of a pathological diagnosis, which correlates with the diverse clinical and radiographic presentations of eosinophilic granuloma in the jaws. In the present paper we report a rare case of unifocal eosinophilic granuloma of mandible occurring in an adult female.