Differentiated thyroid carcinoma is rare in childhood and shows different characteristics as compared to thyroid carcinoma in adults. The male/female ratio is different, it has a higher aggressiveness, locoregional and distant metastases are frequent, response to surgery and 131I radioiodine therapy is optimal. A better knowledge of these characteristics has resulted in the understanding of some relevant aspects of the pathogenesis and natural history of the disease, the suitability of the therapeutic approach and the incidence of adverse side-effects. The increased incidence of differentiated thyroid carcinoma in childhood following the Chernobyl nuclear accident of April 1986 renewed the interest of the scientific community and the public opinion and allowed an in-depth study of some important aspects correlated with the carcinogenic effect of ionizing radiation.