In this article, we analyze the clinical and biological data concerning the autoimmune thyroid diseases in patients recruited in an endocrinology clinic at the university hospital center of Hôtel-Dieu de France between March 2005 and November 2005. We studied 121 patients (51 with Basedow disease and 70 with Hashimoto thyroiditis), between 13 and 68 years old, with a BMI of 24.68 kg/m2 and with a female predominance (105 women). Symptoms of hyperthyroidism represented the most frequent cause of consultation. The distribution of patients regarding their thyroid disease showed that 42.1% of patients had hyperthyroidism (only one patient had subclinical hyperthyroidism), 21.5% had a subclinical hypothyroidism, 28.1% had clinical hypothyroidism and 8.3% had euthyroid goiter. Half of the patients had at least a member of their family whith a thyroid disease. The autoimmune thyroid diseases are strongly associated to other autoimmune diseases and to repetitive spontaneous abortion. Thus, 39% of the married women had had at least one spontaneous abortion and 26.4% of the patients had one or more autoimmune disease associated to their thyroid disease; diabetes mellitus type 1 representing the most frequent one. Concerning the treatment, we remarked a remission of 30 patients (66.7%) with Basedow disease after 18 months of antithyroid drug treatment of 45 patients. In Hashimoto thyroiditis, we remarked a frequent evolution of patients with subclinical hypothyroidism to overt hypothyroidism when medical treatment was not initiated.