The calcifying odontogenic cyst(COC) is considered to occupy a position between a cyst and an odontogenic tumor-having charateristics of both. Gorlin and col. described the COC for first time as an own pathological entity in 1962. Clinically, the COC represents 1% of the odontogenic lesion. It is possible to be found from the first decade to the eight decade but is more frequent during the second decade. It affects in same proportion the maxilla and jaw, being the most in tooth-bearing area of the jaw. This case of COC associated with an unerupted tooth which appeared in the right mandible of 22-year-old woman, was reported. This case report is to present a review of the literature relates to this case of COC and its treatment, discuss clinical, radiographic, histological and therapeutic aspects.