166 patients suffering of Graves' disease have been treated between 1967 and 1971 with 4 different methods (Carbimazole alone, Carbimazole + Surgery, 131 I, 131 I + Carbimazole between 10th and 50th days). The choice was conducted by the volume of the gland and the age of the patient. Isotope was calculated to deliver 7 000 rads in 76 cases and 10 000 rads in 17 more severe cases (cardiothyreosis). 129 patients were submitted to a long term follow up. Medical treatment gave euthyroidism in 34/47 after a mean duration of 8 months. 1/3 to 1/2 of the patients relapsed between 1 to 9 years. Surgical treatment was successful in 25/26 after a total period of 5,5 months. 8 relapsed and 3 became hypothyroid. Relapses were more frequent after bilateral subtotal thyroidectomy than after total lobectomy + subtotal contralateral lobectomy. Isotope gave a complete cure in 14 patients (delay 4,1 months) and in 34, a complementary treatment was necessary (delay 13,5 months). Relapses (12/94) were detected in general after 2 years. The results were the same after 7 000 ans 10 000 rads doses and in the patient receiving, or not, systematically carbimazole. The treatment of Graves' disease is long and difficult. An excellent result is obtained only in half of the cases. 1/3 of these good results needs less than 6 months and 2/3 12 months. A thyroid of less than 40 g include after surgical treatment or after isotopic irradiation an increasing risk of hypothyroidism.