The benign cementoblastoma is an odontogenic tumor originated from neoplastic cementoblasts, a rare lesion mainly associated to impacted and deciduous teeth. It affects mostly young people with an average age of 20 years old, and its preferred location is in the posterior region of the mandible; the lesion will present itself fused both radiologically and microscopically to a root of an erupted permanent tooth, and the anatomopathological diagnosis is obtained through the analysis of the piece sent together with the involved dental element.The present study presents a case of cementoblastoma in the mandible involving the second deciduous molar tooth and preventing the eruption of the premolar tooth in a girl aged 11 years old.This report discusses relevant aspects concerning clinical, radiographic, and histopathological characteristics and treatments.