This document reports on the first case of a cemento ossifying fibroma of the paranasal sinus treated with radiation therapy in a human. A 45-year-old female presented with a large maxillary tumor involving the bilateral maxillary sinuses and orbit. Surgery was deemed unfeasible due to the extensive size and involvement of surrounding structures. Radiation therapy was administered, achieving a dose of 50Gy over 5 weeks. Follow-up showed decreased symptoms, tumor volume reduction from 250cc to 170cc, and no significant adverse effects, demonstrating radiation as a potential treatment option when surgery is not possible.