Long term prognosis of differentiated thyroid carcinoma is favourable, being modulated by several factors, age and histology being the most relevant. Initial treatment includes firstly surgery: loboisthmusectomy in case of intra-thyroid tumor, unifocal, less than 1.5 cm in diameter in patients with favourable prognostic indicators, total thyroidectomy with the administration of an ablative dose of 131l in all the other patients. A routine dissection of the paratracheal groove and of the supraclavicular area is performed in all patients. L-thyroxine treatment is given to all patients. Relapses should be discovered early; this is made possible by the combined use of serum thyroglobulin measurements and of 131l total body scans.