Aim: In this study, our aim is to evaluate the insulin resistance and quality of life in obese subjects and nonobese subjects and to find out the Vitamin D (VD) status and correlations between obesity and control groups and also according to their quality of life scores. Materials and Method: The study was carried out between May and October 2013 which is the period of VD synthesis in Turkey. The participants of this study were volunteering individuals - obese and nonobese individuals defined according to the body mass index (BMI) - that did not receive any VD support in the last 1-year and did not have any known chronic diseases. 1,25-OH VD status and homeostatic model assessment insulin resistance (HOMA-IR) values were evaluated. Results: The study population consisted of 39 individuals with normal weight (23 women, 16 men) and 66 individuals categorized as obese (51 women, 15 men). The difference in HOMA-IR and VD values between the group of obese individuals and the group of nonobese individuals was significant (P < 0.001 vs. P < 0.001). The median value of HOMA-IR was higher in the obese group than in the nonobese group (P < 0.001) while the median value of VD was higher in the nonobese group than in the obese group (P < 0.001). The results regarding the relationship of BMI with HOMA-IR and VD show that there was a positive correlation between HOMA-IR and BMI (rs = 0.507; P < 0.001) and there was a negative correlation between HOMA-IR and VD (rs = 0.316; P = 0.0001). Conclusion: Given serious diseases associated with low serum VD levels such as diabetes and cardiovascular disorders as well as low side effect incidence and low cost of VD treatment, it would be a reasonable approach to identify routine serum 25(OH) D and/or 1,25-OH VD levels of obese patients and administer a treatment to patients with low levels of VD.