Graves' orbitopathy (GO) is part of an autoimmune disease, in which TSH-receptor antibodies (TRAb) stimulate the target organs. Most of these patients develop hyperthyroidism and about half an orbitopathy. To ensure the diagnosis, TRAb are determined, especially in patients with GO without associated thyroid disease. Because of their significantly improved sensitivity and equal specificity, second generation TRAb-assays should be preferred. Persisting high TRAb levels are associated with a severe course of GO. TRAb cut off levels are available for prognostic statements during the course of GO and can be applied for crucial treatment decisions. Persisting high TRAb levels are also associated with low remission rates of hyperthyroidism. TRAb cut off levels are available for prognostic statements at 6, 12 and 18 months after the beginning of antithyroid drug treatment. Definitive treatment of the thyroid can be decided early on this basis, which is an advantage for ophthalmosurgical rehabilitation.