Background: Polycystic ovarian syndrome (PCOS) is a metabolic disorder with an impact on the reproductive, metabolic, and cardiovascular health disease of women. It affects approximately 5%-10% of women in the reproductive age groups. The disorder can be morphological polycystic ovaries or predominantly biochemical hyperandrogenism, a clinical hallmark of PCOS, which can cause inhibition of follicular development, micro cysts in the ovaries, anovulation, and menstrual changes. Aims and Objective: A Correlative Study of C3 in Women with Polycystic Ovarian Syndrome. Materials and Methods: This was hospital based cross-sectional study carried out among PCOS was conducted in the Department of Obstetrics & Gynecology, Index Medical College Hospital, and Indore. This study was conducted from 1st January 2018 to 31st December 2019. A total of 260 subjects with age group between 15 to 45 years were divided into two group; cases (130) and controls (130). Results: Among a total of 260 cases, based on clinical and different biochemical parameters, 130 were diagnosis with PCOS and 130 were healthy women. The mean ±SD of various parameters among PCOS cases were; body mass index (BMI) 32.97±8.466, total cholesterol (TC) 188.42±31.126, triglyceride (TG) 134.43±50.01, high density lipoprotein (HDL) 36.29±9.55 TC/HDL ratio, 5.54±1.865 serum C3, 160.66±29.155 versus BMI 22.87±2.470, TC 155.42±26.333, TG 110.00±42.19, HDL 41.22±10.912, TC/HDL ratio 4.08±1.39, serum C3 127.48±35.60in healthy control. Conclusion: In this study, the role of inflammation and different biochemical markers were studied among PCOS cases. It was found that a majority of the PCOS patients were obese having insulin resistance. The levels of C3 as a marker of chronic low grade inflammation were higher in newly diagnosed PCOS as compared to the controls. The C3 values correlated well with various physiological and biochemical parameter.