ABSTRACT Background: Polycystic ovarian syndrome (PCOS) is one of the most important reproductive and endocrine disorders in women at reproductive age. It's associated with metabolic disorder, obesity, insulin resistance and oxidative stress chronic periodontitis and PCOS both of them associated with low chronic grade of inflammation. The prevalence of periodontal disease seems to be higher in women with PCOS. Superoxide dismutase enzyme (SOD) is an important circulating marker and protecting enzyme helping the body tissues to get rid of reactive oxygen species (ROS) that damage the tissue. Aim of the study: The aim of this study was to measure and compare the levels of (SOD) among group of chronic periodontitis patients with PCOS, group of chronic periodontitis without PCOS and a third group who were systemically and periodontally healthy. Material and Method: This study consist of (60) women at reproductive age ranged between (25-40) years old. They divided into three groups Group I consist of 20 women systemically healthy and with healthy periodontium, group II consist of 20 women with chronic periodontitis and systemically healthy and Group III consist of 20 women with chronic periodontitis and (PCOS). We evaluated the periodontal health of the groups through measuring these important indices: Plaque index, gingival index, bleeding on probing, probing pocket depth and clinical attachment loss. SOD antioxidant marker was measured colormeterically for the three groups. Results: this study showed higher means of periodontal parameters (plaque index, gingival index, bleeding on probing, probing pocket depth and clinical attachment loss (1.275±0.246, 1.295±0.239, 0.24±0.16, 6.47±0.345, 4.125±0.328 respectively). Highly significant differences were found using t-test in inter group comparison. (P≤0.001) regarding pocket depth and clinical attachment loss .Higher mean of (SOD) level was found for G3 (137.72±29.769) U/mL . F-test was used for intragroup comparison and highly significant difference was found (P≤0.001). Positive but weak correlation where found among (SOD) level, bleeding on probing in Group I and Group II , also among (SOD) level, probing pocket depth and clinical attachment loss. Conclusion: (PCOS) associated with oxidative stress and more prone to periodontal diseases with high level of antioxidant agent like (SOD) level to compensate the high level of (ROS)