Thyroglossal duct cysts are the most common anomaly in thyroid development. Generally, duct cysts are benign, but 1 per cent of cases may be malignant. Tumors of the thyroglossal duct are very rare and are usually papillary thyroid carcinomas. In most cases the diagnosis is only established after excison of a clinically benign thyroglossal duct cysts. The etiology of such tumors is unclear, but do novo origin and spread from a primary thyroid gland tumor has been suggested. We reported a case of papillary carcinoma arising in a thyroglossal duct cyst treated successfully with surgical excision in 37-year-old-female.