Introduction: Polycystic ovary syndrome (PCOS) is the most common endocrinological syndrome among reproductive-age women. Oxidative stress (OS) elaborates on PCOS pathological process. OS is a state where oxidative powers exceed the antioxidant systems, serum's ability to reduce the free radical's formation and protect the cell from oxidative stress. TAC protects the cell from the harmful effects of radicals. Examples are superoxide and radical hydroxyl ions. Any change in the level of plasma's antioxidants or oxidative stress can disturb TAC. Aim of the study: This study evaluated serum Total Antioxidant Capacity (TAC) levels in PCOS patients compared to the healthy control group. Methods: The women with PCOS were considered cases and TAC levels compared to healthy women. All were recruited from outpatient clinics in the Duhok governorate in Iraqi Kurdistan between November 2021 and February 2022. One hundred twenty women (60 PCOS patients and 60 healthy subjects). PCOS was diagnosed according to the Rotterdam criteria (2003). All patients underwent clinical assessment. Results: The PCOS patients and controls were similar in age and BMI. The PCOS showed highly significant differences in the clinical parameter as hirsutisms. Patients with PCOS are likely to have a morphology of>12 follicles per ovary (95.0%) in contrast to <12 follicles per ovary (93.33% in the controls (P<0.0001). The PCOS patients had substantially higher volumes of the right and left ovary than the controls (P=0.0008). A similar pattern was found for the morphology of the left ovary. This study showed highly significant differences in the mean concentration of testosterone in PCOS patients, which was significantly higher (0.31) compared to its attention in the controls (0.19; P<0.0001). PCOS patients had a substantially lower level of TAC (2.24) compared to the controls (2.51; P<0.0001). These parameters showed in PCOS patients on the level of TAC; all parameters have no significant effect except for age. Conclusions: This study revealed that the serum TAC levels are significantly lower in PCOS patients than in control patients.