Polycystic Ovary Syndrome is a multifactorial reproductive problem and a leading cause of female infertility worldwide. Evidences have shown that Oxidative Stress and decreased antioxidant status are often linked with PCOS. Insulin Resistance in PCOS patients ranges from 50% to 70% and may encourage OS by production of reactive oxygen species. Objective: Our study determines serum MDA levels along with plasma glucose, serum insulin, and insulin resistance in obese and nonobese PCOS subjects. Materials and methods: A case control study was conducted on diagnosed 100 PCOS patients and 100 controls. Fasting plasma glucose was measured by enzymatic method. Insulin was estimated by chemiluminescent microparticle immunoassay using Abott Architect i 2000 SR analyser. Insulin resistance was calculated by HOMA-IR. Malonaldehyde is determined as Thiobarbituric acid reactive substances. Results: CRP and serum MDA levels were increased in women with PCOS irrespective of obesity compared to their respective controls with a p value of <.001. However, though fasting glucose, serum insulin, and IR were increased in both obese and nonobese women with PCOS compared to their BMI adjusted controls with p value of <.001, the values were within reference range in nonobese women. Conclusion: Our study suggests that women with PCOS have oxidative stress and elevated CRP irrespective of obesity. However, hyperinsulinemia and Insulin resistance are seen only in obese women with PCOS, indicating that these women are at high risk for developing low grade inflammation and cardiovascular diseases. © 2018, © 2018 Informa UK Limited, trading as Taylor & Francis Group.