An abnormally elevated androgen level in reproductive-aged women causes development of ovarian cysts, leading to ovulatory infertility, irregular menstruation, increased risk of insulin resistance, cardiovascular problems, amenorrhea, obstructive sleep apnea, cardiovascular disease, hirusitism, acne, and depression, postpartum hemorrhage, endometrial carcinoma, type 2 diabetes mellitus (T2DM), hyperglycemia, gestational diabetes mellitus (GDM), which can result into ROS formation, oxidative stress, and abdominal adiposity. The reproductive, endocrinal, metabolic and ovarian disorders are collectively known as PCOS (polycystic ovary syndrome). In about 70% of PCOS women, disrupted GnRH, FSH, LH, prolactin levels and obesity further prejudice insulin metabolism or insulin resistance. A peptide hormone Leptin, which is encoded by the obese, was found to be higher in PCOS women and now seems to be emerging as an important biomarker, as excessive leptin levels in PCOS may disrupt ovarian steroidogenesis and mature oocyte development, which could lead to ovulatory dysfunction and infertility. TNF-α and IL-6 are the inflammatory cytokines found in high concentration in PCOS women, that share close relation with leptin. Therefore, leptin, agonist and antagonist of leptin could be a novel prospective biomarker for diagnosis, prevention, treatment and cure of polycystic ovary syndrome.