At the 15th conference on the human thyroid in Heidelberg in 2001 the following aspects of the radioiodine therapy of benign thyroid disorders were presented: General strategies for therapy of benign thyroid diseases, criterions for conservative or definitive treatment of hyperthyroidism as first line therapy and finally preparation, procedural details, results, side effects, costs and follow-up care of radioiodine therapy as well as legal guidelines for hospitalization in Germany. The diagnosis Graves' hyperthyroidism needs the decision, if rather a conservative treatment or if primary radioiodine therapy is the best therapeutic approach. In the USA 70-90% of these patients are treated with radioiodine as first line therapy, whereas in Germany the conservative therapy for 1-1.5 years is recommended for 90%. This review describes subgroups of patients with Graves' disease showing a higher probability to relapse after conservative treatment. Comparing benefits, adverse effects, costs, and conveniences of both treatment strategies the authors conclude that radioiodine therapy should be preferred as first line therapy in 60-70% of the patients with Graves' hyperthyroidism.