Objectives: The relationship between Insulin Resistance (IR) and both clinical and subclinical hypothyroidism is well documented. Hashimoto's Thyroiditis (HT) is the most common cause of hypothyroidism. In this study, we aim to reveal whether a relationship exists between insulin resistance and euthyroid Hashimoto's thyroiditis. Material and method: The study included 55 patients with Positive Thyroid Autoantibodies (PTA) euthyroid Hashimoto's Thyroiditis (HT) and 55 healthy control groups. Insulin, Thyroid Stimulant Hormone (TSH), thyroid autoantibodies such as Anti-Thyroid Peroxidase (Anti-TPO) and Anti-Thyroglobulin (Anti-Tg), Homeostasis Model Assessment (HOMA) index, and fasting blood glucose, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and total cholesterol levels of patients and a control group were compared. Results: Age, gender, Body Mass Index (BMI), Thyroid Stimulating Hormone (TSH), Free Thyroxine (FT4), and Free Triiodothyronine (FT3) did not differ between patients and the control group. Fasting glucose levels (p: 0.006); insulin levels (p: 0.011); Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) values (p: 0.011); low-density lipoprotein cholesterol levels (p: 0.008); high-density lipoprotein cholesterol levels (p: 0.041); triglyceride levels (p: 0.008); and total cholesterol levels (p: 0.002) were significantly higher among patients with positive thyroid autoantibodies than control subjects. We found a positive correlation among thyroid stimulating hormone, anti-thyroid peroxidase, anti-thyroglobulin, and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) levels (p<0.001). Conclusion: High thyroid autoantibodies levels are related to high fasting blood glucose levels, insulin levels, lipid parameters, and Homeostasis Model Assessment-Insulin Resistance (HOMA-IR) values. These findings indicate a possible relationship between insulin resistance and autoimmune thyroiditis and thyroid stimulating hormone levels. Patients with positive thyroid autoantibodies should be followed closely for diabetes mellitus and cardiovascular events.