Objective: Two rare cases of calcifying epithelial odontogenic tumors are presented (an extraosseous and an intraosseous lesion) . Methods: The tumor tissues were examined by routine HE staining , PAS and congo red staining. CD1 ¦Á, CD 68 , HLA-DR , S-100 protein and CK19 antibodies were used immunohistochemically to examine Langerhans cells. The intraosseous lesion was also ultrastructurally investigated. Results: The tumor chiefly consisted of scattered small nests and cords of epithelial cells and clear cells with vacuolated cytoplasm. Scarce calcification of homogenous materials was observed. There was little homogenous materials could be seen in extraosseous lesion. There were a few; occasionally several; cells positive for CD1¦Á , CD 68, HLA-DR and S-100 protein; tumor cells were positive for CK19 and amyloid material were negative; Ultrastructural studies found Langerhans cells with indented nuclei and Birbeck's granules among tumor cells. Conclusions: Ultrastructural analysis detected Langerhans cells with indented nuclei and Birbeck's granules among tumor cells and positive immunoreactivities for CD1¦Á , CD 68, HLA-DR and S-100 protein suggested that the two cases be calcifying epithelial odontogenic tumor with Langerhans cells.