Autoimmune thyroiditis (AIT) is the most common organ-specific autoimmune diseases in humans. It is characterized by the presence of circulating antithyroid autoantibodies (TAAs). The aim of our study was to evaluate the diagnostic performance of antithyroperoxidase (anti TPO), antithyroglobulin (anti TG) and anti TSH receptor (anti RTSH), during thyroid and non-thyroid autoimmune diseases (AID). This is a descriptive retrospective study over a period of 30 months (January 2019 June 2021), which included 130 adult patients hospitalized at the Ibn Sina University Hospital in Rabat. The average age was 46 ± 15 years. Women accounted for 107 cases (82.30%), representing a sex M/F ratio of 0.21. Our series showed 82 patients who were in euthyroidism, 29 in hypothyroidism and 19 in hyperthyroidism. Anti-TPO positive were found in 118 patients, of whom 90.7% (n=107) had Hashimoto's thyroiditis and 6.7% (n=8) had Basedow's disease. Of the 66 patients with anti-TG-positive drugs, 89.4% (n=59) had Hashimoto's thyroiditis and 7.6% (n=5) had Basedow's disease. Anti-RTSH antibodies were found in 6 patients, all with Basedow's disease. AITs were associated with autoimmune non-thyroid conditions in 59.23% (n=77) of patients; type 1 diabetes was most prevalent in 30.76% (n=40). In conclusion, a high presence of TAAs was found in the context of euthyroidism with a wide range of AIDs. This requires careful interpretation in order to accurately determine their actual clinical significance outside an AIT context.