It is the most common benign tumor that can be seen significantly. It is common odontogenic tumor involving the molar ramus area. As this tumor shows some similarities with dentigerous cysts, both clinically and radiographically the biologic behaviour of this tumor group was reviewed. The recurrence is more in unicystic ameloblastoma and patient has to have the long time followup. Here we are presenting a case of unicystic ameloblastoma in 55year female who has got edentulous ridge. Keywords: Rests of dental lamina, From a developing enamel organ, From the epithelial lining of an odontogenic cyst, Or from the basal cells of the oral mucosa.