We report a rare case of desmoplastic fibroma that originated in the maxillary alveolus of an 84-year-old woman. CT demonstrated a large osteolytic intraosseous mass extending to the maxilla and nasal cavity. The curettaged mass, which was 3×3×5 cm in size and had an oval shape, consisted of spindle cells separated by abundant collagen fibers. Immunohistochemical analysis revealed that the spindle cells had a fibroblastic origin. These features may be confused with well-differentiated fibrosarcoma, another type of intraosseeous fibrous lesion. However, the cells were not atypic and were negative for Ki-67. Thus, the present case was diagnosed as a desmoplastic fibroma. Desmoplastic fibroma originating in the maxillary alveolus is extremely rare (3 reported cases, including the present case). The present case is characterized by the age of the patient, 84 years, which is higher than in previous reports.