Persistence of embryonal thyroglossal duct attributes to the development of thyroglossal duct cyst and fistula. We experienced 3 cases of thyroglossal duct cysts and fistula, recently and report them. The patients were 39 year-old and 15 year-old male, and 42 year-old female, and shhowed palpable mass in the midline position of the neck around the hyoid bone. They were all treated with Sistrunk's procedure. Histopathological study made final diagnoses.