The thyroid gland originates from the foramen cecum, and by 7 weeks gestation, descends ventrally in the midline of the neck. During its descent, a patent diverticulum, the thyroglossal duct, connects the gland to the base of the tongue. While the duct normally closes by the tenth gestational week, it is not uncommon to have all or a portion of the duct remain patent as a thyroglossal duct cyst or sinus. While these cysts are relatively common, thyroglossal duct carcinomas are very uncommon. They are generally of two types: squamous cell carcinoma arising from metaplastic columnar cells, and thyrogenic carcinoma arising from thyroembryonic rests in the duct or cyst. We report one case of each. The squamous cell carcinoma was resected via the Sistrunk procedure with no evidence of recurrence over a 10-year follow-up. The thyrogenic carcinoma (papillary type) was resected via the Sistrunk procedure with subsequent total thyroidectomy.