Thyroid cancer in childhood is a relatively rare condition. Often it shows biological characteristics different from those seen in adults. Based upon 10 cases in our clinic and 57 cases collected from the Japanese literatures, clinical features, pathology, treatment and prognosis of thyroid cancer in childhood are discussed. Pathogenesis is most likely to be related to hormonal changes during adolescence and previous radiation of the neck region. Cervical lymph nodes swelling was the chief complaint in 84.6 per cent of the cases. On the other hand, pulmonary metastases were recognized in the early stages in 33.5 per cent of the cases. Radical excision of the tumor with modified radical neck dissection is the treatment most frequently employed even in the presence of lung metastases. However, hypoparathyroidism and recurrent nerve injuries should be avoided at all cost in view of long life expectancy and the difficulty in treating them satisfactorily. Prognosis could be as good for children as it is for adults except in cases with early lung metastases.