Odontogenic cysts are relatively common pathologic lesions found in the oral and perioral structures, but the case of squamous cell carcinoma arising from those cysts are very uncommon. After first reported of that case in 1889 by Herman, Schwimmer collected 56 cases of previously reported squamous cell carcinoma arising in residual odontogenic cyst during about past one century. More than 60% of cases of carcinoma developing in odontogenic cysts arising in inflammatory periapical or residual cyst, and these tumors are usually well-differentiated with relatively good prognosis, and often are diagnosed as benign lesion in radiographic or clinical examination, therefore definitive diagnosis must be made by histologic examintation. We report a case and review the literatures, in our case, 78-year old woman were clinically and radiographically diagnosed as residual odontogenic cyst. But in histologic examination after enucleation of lesion, mass of squamous cell carinoma were observed, but in other area, typical cyst wall and lining epithelium were observed. And in some area, carcinoma in situ and invading squamous cell carcinoma into the lining epithelium were also observed.