It has previously been proposed that subclinical Yersinia enterocolitica infection may play a role in autoimmune thyroid disease (AITD). In this study, we investigated the relationship between the thyroid autoantibodies and the antibodies that produced against different serotypes of Y. enterocolitica. A total of 215 subjects were included into the study (65 newly diagnosed Graves' disease [GD], 57 Hashimoto's thyroiditis [HT], 53 nontoxic diffuse goiter [NTDG], and 40 subjects for control group [CG]). Thyroid receptor antibodies (TRAb), thyroid and agglutinating antibodies against Y. enterocolitica serotype O:3, O:5, O:8, O:9 were measured in the blood samples. The highest incidence of Y. enterocolitica antibody positivity was measured in GD (53.8% for O:3, 29.2% for O:5, 44.6% for O:8, and 40% for O:9) and followed by HT. In patients with GD, TRAb levels were also higher than in patients with HT, NTDG, and CG. There was no difference between NTDG and CG in respect to the titer levels and the positivity of both TRAb and Y. enterocolitica antibodies. There was also a weak linear correlation between TRAb level and the titer of antibodies against Y. enterocolitica antigens. It can be concluded that Y. enterocolitica infection may play a role in etiology of GD in Turkey.