Primary carcinoma of the thyroglossal duct is rare. This discussion reports two cases and reviews the 50 previously reported in the literature. The criteria for diagnosis include evidence of a thyroglossal duct remnant and a normal thyroid gland. The differentiation from cystic metastases to lymph nodes is pointed out. The histologic types parallel those of carcinoma of the thyroid gland, papillary carcinoma being the most common and having a generally favorable prognosis. The clinical presentation of these tumors is similar to that with benign cysts and thus is of limited value in the diagnosis.