Aneurysmal bone cyst (ABC) is rare benign lesions of bone which are infrequent in craniofacial skeleton. ABC's are characterized by rapid growth pattern with resultant bony expansion and facial asymmetry. We describe a case of ABC in a 25 year old male patient affecting the body of the mandible with expansion and thinning of the buccal and lingual cortical plates. Treatment consisted of surgical curettage of the lesion. A one year follow- up showed restoration of facial symmetry and complete healing of the involved site.