Eight hundred and ten pedigree members of 110 patients with Graves’ disease were studied. In 700 first-egree relatives, inquiry of medical history, physical examination (including eyes, thyroid, heart rate, etc), thyroid function tests (serum T3, T4 and TSH levels), determinations of thyroglobulin antibodies (TgAb) and thyroid microsomal antibodies (TmAb) were performed. For male (female) probands, the incidence of Graves’ disease in male (female) first-degree relatives were investigated and their serum TgAb and TmAb were analysed. The incidence of these two kinds of autoantibodies in the male (female) first-egree relatives of familial and nonfamilial Graves’ disease were analysed. Eighteen persons with positive TgAb and TmAb from 5 pedigrees had been followed up one year after initial determinations. Our results suggest that the positive rates of TgAb and TmAb in the first-egree relatives of Graves’ disease were coincident with the incidence of Graves’ disease, and the positive results of TgAb and TmAb Eight hundred and ten pedigree members of 110 patients with Graves’ disease were studied. In 700 first-egree relatives, inquiry of medical history, physical examination (including eyes, thyroid, heart rate, etc), thyroid function tests (serum T3, T4 For male (female) probands, the incidence of Graves’ disease in male (female) first-degree relatives were investigated and their serum TgAb (TgAb) and thyroid microsomal antibodies (TmAb) were performed. and TmAb were analyzed. The incidence of these two kinds of autoantibodies in the male (female) first-egree relatives of familial and nonfamilial Graves’ disease were analysed. Eighteen persons with positive TgAb and TmAb from 5 pedigrees had been followed up one year after initial results that the positive rates of TgAb and TmAb in the first-egree relatives of Graves ’disease were coincident with the incidence of Graves’ disease, and the positive result s of TgAb and TmAb