For malignant neoplasms of salivary tissues. two of the better determinants of progosis are histologic classification and size of the neoplasm. Proper management of these tumors requires an accurate diagnosis by the pathologist and correct interpretation by the surgeon. Malignant mixed tumors account for between 3 and 13 precent of all cancers of the salivary glands and 2 percent of all tumors in these locations. The typical history of these tumors is that of slowly growing mass demonstrating a sudden increase in growth. The duration of onset of the tumor mass and the diagnosis of malignancy has been demonstrated to be 10 to 18 years. The risk of malignat transformation of a benign mixed tumor increases with the duration of the tumor. We analyzed retrospectively 13 cases of malignant mixed tumor who visited from Jan. 1985 to Dec. 1992. Mean age of the patients was 56.5 years. The origin of tumors were parotid gland 7 cases, submandibular gland 2 cases, and minor salivary gland 4 cases(palate 3 cases, tonsil pillar 1 case). According to the criteria of the AJCC on staging, stage I was 1 case, stage II 1 case, stage III 2 cases, and stage IV 9 cases. Histopathologically, carcinma ex pleomorphic adenoma were 12 cases and the true malignant mixed tumor was 1 case. The major treatment modalities were curative surgery, and radiation therapy followed. In conclusion, aggressive therapy of combined surgery and postoperative radiation therapy is required for these lesions, and patients with known or suspected benign tumor should be encouraged to undergo surgery early on in their disease to avoid malignant degeneration at a later dete.