Cemento-ossifying fibromas are one of the neoplastic benign fibro-osseous lesions. Radiographically, cemento-ossifying fibromas can be differentiated with non-neoplastic benign fibro-osseous lesions by their well-circumscribed margin. Mostly, they occur in mandibular bone. Some of them are in paranasal sinus, which are more invasive, even in slow progression, and an agressive surgical intervention is necessary. This case is a 16-year-old boy complaining nasal obstruction, nasal bleeding and headache. Physical examination and image study revealed ossifying fibroma. Endoscopic near-total resection was performed, and pathologic exam showed cemento-ossifying fibroma. We have followed this case for two and a half year, and no significant complications or recurrence are presented.