Cemento osseous dysplasia (COD) is a lesion that occurs in the periapical and tooth-bearing area where normal bone tissue is replaced by fibrous tissue and metaplastic bone. The cause is not clearly known. COD is often discovered incidentally without any symptoms. It is more common in females and mandibular molars. The involved tooth is vital. In radiological imaging, the lesion has a well defined border. The internal density of the lesion depends on the maturity of the lesion. Radiolucent and mixed lesions of COD are sometimes mistaken for periapical lesions and root canal treatment is performed. Because COD has limited growth, no special treatment is required. Accordingly, The author reports cases of COD in mandibular teeth region referred from other clinics for accurate diagnosis or removal of the lesions and presents the cone beam computed tomography images of the cases to help clinicians make an accurate diagnosis.