A great deal has been written about ossifying fibroma and fibrous dysplasia. Many authors regard ossifying fibroma as a part of the monostotic fibrous dysplasia, others maintain that ossifying fibroma constitutes a separate clinical and histological entity. The current accepted theory is that ossifying fibroma is a distinct entity and able to be distinguished by distinct clinical, radiological and histological criteria. Recently, authors experienced a case of ossifying fibroma which occupied the right maxillary sinus in a 16 year old female on August 25, 1987, the tumor mass removed by Fergusson incision under general anesthesia, and there is no evidence of recurrence at the present time.