Objective: Polycystic ovary syndrome (PCOS) is the most common endocrine disorder of reproductive women. It is affecting from 5-10% of women in reproduction age. The symptoms include infertility, hirsutism and acne, menstrual abnormalities, Obesity and may cause endometrial cancer, cardiovascular disorder and diabetes mellitus. Leptin, the product of the ob gene, is a small peptide molecule synthesized by white adipose tissues with an important role in the regulation of fat body and food intake. Although the role of leptin in the control of reproduction is unclear, but it may be involved in the control of ovulation. Radical Oxygen Species play a physiological role throughout ovulation. The antioxidant (Vitamin E and Selenium) have important role in infertility and in PCOS. Materials and Methods: This study included twenty-five untreated women with clomiphene citrate, twenty-six treated with clomiphene citrate and twenty-four control women matched- body mass index (BMI), each of these groups are subdivided to three subgroups according to menstrual cycle phases. Fasting blood samples were collected. Concentrations level of parameters in serum was analysed (Leptin by Enzyme-linked immosorbent assay (ELISA) which is based on sandwich principle, Estradiol (E2) by Mini- Vidas which combines a competitive method with a final fluorescent detection (ELFA) Enzyme linked fluorescent assay, Vitamin E by High performance liquid chromatography (HPLC), and Selenium (Se) by flameless atomic absorption spectrophotometer (AAS) ). Results: During the three phases of Menstrual cycle (M.C.), there are a significant difference between follicular and pre-ovulation phase (leptin, estradiol, vitamin E, selenium; P<0.001, P<0.0005, P<0.05, P<0.01. respectively) for treated and control groups, while untreated (P<0.05, P<0.005, N.S., P<0.01. respectively). Also there are significant difference between pre-ovulation and luteal phase for estradiol (P<0.0005) in control and treated groups. Serum leptin concentrations were not different in subjects with groups of PCOS and controls matched- BMI, and were associated BMI with positive correlation for each group (Untreated, Treated, Control; r=0.895, r=0.847, r=0.823 respectively). While serum estradiol and vitamin E have significant between PCOS groups and controls in pre-ovulation period (P<0.0005), and serum estradiol concentrations positive correlation with BMI only in untreated PCOS(r=0.531), also serum estradiol concentrations have positive correlation with leptin in follicular phase (Untreated, Treated, Control; r=0.915, r=0.898, r=0.786 respectively). Selenium have highly significant difference between PCOS groups and control in each phase of M.C. (P<0.000005) and there are no association between selenium and vitamin E with BMI. Conclusion: The results indicated that leptin concentrations do not differ significantly between PCOS patients and control with clear positive correlated with BMI. Leptin have a role in follicular growth by their relation with estradiol at which indirect effect to selenium. Vitamin E has a role in ovulation. In untreated PCOS lower level of Selenium and vitamin E suspecting of oxidative stress is occurred.