Papillary and follicular thyroid carcinomas are among the most curable of all cancers. However, some patients are at high risk of recurrence or even death from their cancer. Most of these patients can be identified at the time of diagnosis using well-established prognostic indicators. The extent of initial treatment and follow-up should therefore be individualized. The early discovery of persistent and recurrent disease is based on the combined use of serum thyroglobulin determination and of total body scanning with 131I. The recent availability of recombinant human thyroid stimulating hormone has greatly improved the quality of the patient's life during follow-up. Treatment of recurrences is based mainly on surgery and 131I treatment.