Cemento-ossifying fibroma (COF) is a rare benign fibro-osseous tumor. The radiographic and clini‌cal features of this lesion are unpredictable and variable. In this report, the patient was a 12-year old girl with a painless swelling which demon‌strated an opaque lesion with radiolucent zone to involve left posterior portion of the mandible on panoramic radiography. The radiographic manife‌station of this lesion was similar to complex odontoma, but histological findings were com‌patible with COF. Here under, Cone-beam com‌puted tomography (CBCT) findings of this lesion and also its radiographic diagnostic dilemma are discussed.