The aim of this study was to investigate the relationship between insulin resistance and thyroid function in obese pre- and postmenopausal women with or without metabolic syndrome (MetS). 141 obese women were divided into two groups, HOMA-IR<2.7 and HOMA-IR>2.7, to evaluate relation with HOMA-IR and fatness, hormone and blood parameters. They were then divided into four groups as pre- and postmenopausal with or without MetS. Various fatness, hormone and blood parameters were examined. Statistically significant difference was found in weight, body mass index (BMI), waist circumference, fat%, fasting insulin, TSH, FT3, FT4, FSH, Anti-microsomal antibody (ANTIM) and triglycerides levels in HOMA-IR<2.7 and HOMA-IR>2.7 obese Turkish women. This study showed that age, weight, BMI, waist circumference, fat%, fasting insulin, FT3, ANTIM, FSH, LH, total cholesterol, triglycerides, HDL, HOMA-IR, systolic and diastolic blood pressure levels were related in preand post menopausal status in obese women with or without MetS. Obesity may influence the levels of thyroid hormones and increases the risk of MetS in women. Postmenopausal status with MetS is associated with an increased TSH, FT3 and FT4 levels and HOMA-IR in obese women. Strong relation was observed with MetS and TSH and FT3 levels.