Selenium has recently been connected to insulin resistance (IR) and obesity due to its anti-inflammatory and anti-oxidant functions through selenoproteins. thus, the purpose of this study was to determine the relationship between BMI and serum selenium levels in participants with and without insulin resistance and to evaluate whether BMI is affected by selenium and insulin resistance status. (120) Iraqi (men and women) ranging between (18- 60) years old, with varying BMIs (normal weight, overweight, and obese) were included in a cross-sectional study. The Graphite Furnace Atomic Absorption Spectrophotometer was used to measure the serum level of selenium, and the ELISA technique was used to measure the fasting blood level of insulin. Among the 120 subjects, 25 (20.8%) were insulin resistant and 95 (79.2%) were non-insulin resistant. Insulin resistance was found in the group with significantly higher insulin than the non-insulin resistance group (P<0.001). Selenium levels significantly increased in the age group (31-50)   years old but declined in the group of age > 50 years old (P<0.001). Selenium levels were significantly lower in females than males (P=0.001) and significantly decreased with increasing BMI (P<0.001). The findings revealed that serum selenium levels were linked to obesity, independent of insulin resistance.