Thyroglossal duct carcinoma, which is usually diagnosed postoperatively, is a rare malignant tumor arising in the thyroglossal duct cyst. The definitive diag-nosis can be made only after microscopic examination. We retrospectively reviewed three cases of thyroglossal duct carcinoma diagnosed in Peking University School and Hospital of Stomatology from January 1986 to August 2006. Clinical and pathological features were investigated and the optimal treatment protocol was proposed. The constituent ratio of thyroglossal duct car-cinoma among surgically excised thyroglossal duct lesions was 2.9%. The clinical presentation of thyroglos-sal duct carcinoma was very similar to that of its benign counterpart. Two cases were diagnosed as thyroglossal duct cyst prior to the operation, the remaining one as dermoid cyst. All three cases were diagnosed as papillary carcinoma of thyroid origin after microscopic examina-tion. Primary thyroglossal duct carcinoma should con-form to the following criteria: localization of the carcinoma to a clearly demonstrable thyroglossal duct cyst or tract; clinically or histologically confirmed absence of carcinoma of the thyroid gland. Papillary carcinoma is the most common histological type, which usually develops slowly with an excellent Prognosis. The histological characteristics including: formation of pap-illary structure; nuclear morphological variations such as ground glass nuclei, pseudoinclusions, intranuclear grooves and filaments; concentrically calcified struc-tures termed psammoma bodies which is regarded as a strong indication of papillary carcinoma; and positiv-ity in immunohistological staining for thyroglobin. Sistrunk procedure of excision is the choice for treat-ment. A close follow-up is needed. In the presence of thyroid gland masses or cervical lymphadenopathy, thyroidectomy or neck dissection should be recom-mended. The effect of thyroid suppression therapy and radioactive iodine therapy is not conclusive.