The present study aimed to evaluate the role of subcutaneous adipose tissue (SAT) type II deiodinase enzyme gene (DIO2) expression in developing metabolic syndrome (MetS). A total of 51 obese patients with MetS and without MetS and 13 healthy subjects enrolled in the study. Body mass index (BMI), waist circumference (WC), waist-to-hip circumference ratio (WHR), hip circumference, and systolic (SBP) and diastolic blood pressures (DBP) of all subjects were recorded. Fasting plasma glucose (FPG), fasting plasma insulin, high density lipoprotein- cholesterol (HDL-C), low density lipoprotein-cholesterol (LDL-C), total cholesterol (TC) and triglyceride (TG) of all subjects were analyzed. Expression of the DIO2 gene in adipose tissue was determined by reverse transcription polymerase chain reaction (qRT-PCR). BMI, WC and WHR were not significantly difference between obese with and without MetS. SBP, DBP, FPG and TG were significantly higher in obese with MetS group than obese without MetS group. While the free triiodothyronine (T3) level was in the normal range in all group, it was significantly lower in the obese with MetS than both obese without MetS and control group. DIO2 expression was significantly lower in the obese with MetS group compared to the control. In correlation analysis, DIO2 expression was negatively correlated with DBP, TG and homeostasis model assessment of insulin resistance (HOMA-IR) levels and positively correlated with free T3. In conclusion, the reduction of SAT DIO2 expression is negatively correlated with DBP and TG levels that are associated with the MetS. This might have an effect on developing MetS. We believe that DIO2 gene may be an important molecular target for future studies in developing targeted treatment options for obese people with MetS.