Fibrous dysplasia is an idiopathic skeletal disorder in which medullary bone is replaced and disturbed by poorly organized, structually unsound fibroosseous tissue, which may produce cortical expansion. When facial bones are involed, considerable esthetic deformity may result. The term monostotic fibrous dysplasia has been applied when one bone is involved : when more than one bone is affected, the term polyostotic used. The polyostotic form may be accomplished by pigmented skin lesion (Jaffe type), or by pigmented skin lesions with endocrine disturbance (Albright syndrome). No general agreement exists on the cause of fibrous dysplasia. A few authors have suggested that fibrous dysplasia arises as a resujlt of trauma. It occurs predominantly in infant, adolescent females and runs a variable clinical course. When several bones are involed, it tends to be unilateral. Involements of alveolar bone may produce displacement of teeth with malocclusion, or loss of teeth, or both. Radiographycally, it shows an indistinctly delimited osteolytic defect with a bubble - like pattern, but without a sclerotic rim. The preferred treatment is almost always surgery. If the lesion is extensive, surgical intervention with use of recontouring procedures aimed at the correction of esthetic or funtional disturbances is preferred treatment. Now, we present a case of fibrous dysplasia on the left maxilla and the zygoma treated by bony contourign via hemicoronal flap and intraoral approach with good results.