Thyroglossal duct remnants are the most common congenital cystic lesions of the neck, however a carcinoma arising in these structures is relatively uncommon and majority have been papillary adenocarcinoma. Three cases of papillary adenocarcinoma arising in a thyroglossal duct cyst are presented. This rare lesion, which occurs is less than 1% of thyroglossal duct abnormalities, pathologically and clinically is similar to primary tumor arising in the thyroid gland. Therapy consists of wide excision of the tumor-bearing tissue(Sistrunk procedure) in those cases localized to the duct remnant itself and this treatment results in excellent prognosis. Distant metastasis is rare and long-term prognosis is very favorable.