The authors experienced recently a case of ossifying fibroma in left maxillary sinus. A 42-year-old woman was admitted on June 18 1968, with the complaints of painless swelling of left cheek and protrusion of left side of the palate, which had developed gradually for four years prior to admission. Preoperative biopsy revealed an ossifying fibroma. On June 25 1968, the tumor mass removed surgically by Wever's approach under general anesthesia. Postoperative course was uneventful and discharged in good condition.