OBJECTIVE To examine the epidemiological and clinical characteristics of hereditary thyroglossal duct cysts (TGDCs). METHODS A complete English-language literature review, assisted by MEDLINE and BIOSIS, of hereditary cases of TGDC was performed between 1975 and 1996. Three new cases from our institution were included in the study. METHODS Patients with a diagnosis of hereditary TGDC. METHODS All case reports were reviewed by multiple observers to confirm the diagnosis of hereditary TGDC. RESULTS A review of the literature revealed that a hereditary pattern has been described in 18 patients from 6 families; 11 of the 18 cases were reported in the United States. We report 3 new cases of TGDC herein, bringing the total of US cases to 14. In all 14 US cases, the patients were female presented at a mean age of 6.1 years, and had a predominantly autosomal dominant inheritance pattern. These findings are in sharp contrast to those in international cases (n = 7), in which only 29% of the patients were female and the mean age at presentation was much older (16.2 years). An autosomal dominant pattern of inheritance was found in 2 of 3 foreign families. Interestingly, the patients with an autosomal dominant pattern of inheritance were older than those with an autosomal recessive pattern (13.9 years vs 6.2 years, respectively). CONCLUSIONS Cases of hereditary TGDC are female predominant and usually have an autosomal dominant pattern of inheritance. The sexual bias may be explained by genetic imprinting. Although no racial differences were noted in our study, distinct variations in presentation based on nationality were present. The recurrence rate after a Sistrunk procedure is similar to that in nonhereditary cases.