Three cases of lateral periodontal cyst that were diagnosed in the last years in the Pathology and Semiology Chair of theDentistry Faculty - UCU are presented and a bibliographic research of this lesions is made. The lateral periodontal cyst is a developmental odontogenic cyst that was included in 1992 in the World Health Organization (WHO) classifications of cysts of the jaws described by Kramer. Is an uncommon entity notwithstanding the differentialdiagnosis has to be establish with other entities with similar clinical radiographic characteristics but with different aetiology and evolution. For this reason the histological diagnosis is necessary. The microscopy shows a thin non-keratinized epithelium with clear glycogen-containing cells that form plaques. The treatment is the total enucleation and distance control for present although minor the possibility of relapse.