We present a rare case of an ossifying adenocarcinoma originating in the parotid gland. Of a 52-year-old female with complaints of preauricular swelling, jaw trismus and mental nerve paralysis. Panoramic radiography and computed tomography revealed a tumor in the right preauricular region extending to the mandibular head and radiopaque miliary shadows in the lungs. Histopathologically, the tumor revealed characteristics of adenocarcinoma with prominent ossification. The immunostaining for bone morphogenetic protein-2 and osteopontin suggested that the ossification was induced by the tumor cells. Despite chemoimmunotherapy with TS-1 ® and OK-432 ® and later with an epidermal growth factor-receptor antagonist, gefitinib, the original tumor and metastatic pulmonary foci continued to growth and the patient eventually died about 15 months after the start of therapy.