Autoimmune thyroid disease is usually related to the presence of autoantibodies (TPO, TMA, TGA, TSH-R) in patients' sera. In this study the presence of autoantibodies in the sera of patients with thyroid disease, patients with end-stage renal disease and in several groups of euthyroid subjects have been evaluated (N = 217). The percentages of positive values detected in six groups ranged: 0-47%, 2-94% and 3-100% for TGA, TMA, and TPO, respectively. Autoantibodies were mostly present in the sera of patients with Hashimoto thyroiditis (TPO 100%, TMA 94%, TGA 47%), and sporadically in the control subjects (TPO 4%, TMA 2%, TGA 0%). Authors's results confirm the prevalence of TPO over TGA and TMA in the sera of all investigated groups. The authors did not find changes in ATA levels during methimazole therapy of their patients with Graves' disease. Some of serum autoantibodies were constantly present or absent in spite of remission.