Odontogenic cyst and odontogenic tumor shares developmental source. However, they have different histopathologic features, and they are classified respectively. Odontogenic cyst and tumor can share same physical region. It is called a hybrid lesion, a lesion showing the combined histopathological characteristics of two or more previously recognized odontogenic tumor and/or cysts of different categories. In this study, a hybrid lesion was researched. 61-year old man was referred to our department with a multilocular radiolucency in right mandibular angle. Incisional biopsy was carried out, and the patient was diagnosed with ameloblastoma. Odontogenic keratocyst was found with the tumor, and it was thought to be evolved via neoplastic transformation from lining epithelium of the keratocyst. After reviewing studies reporting hybrid lesions from odontogenic cyst and tumor, formation of a hybrid lesion was most frequent from a dentigerous cyst and an adenomatoid odontogenic tumor. A hybrid lesion commonly lead to misdiagnosis, and the prognosis is not always transparent. The close relationship between the odontogenic cyst and tumor has to be kept in mind in the diagnosis and treatment of the lesions in maxillofacial area.