This chapter discusses polycystic ovary syndrome (PCOS) and its clinical manifestations. It also explores the incidence of insulin resistance in PCOS. Insulin resistance can be encountered in women with PCOS. Diagnosis and treatment are also independent on insulin resistance. Management of women with PCOS depends on the symptoms. These could be ovulatory dysfunction-related infertility, menstrual disorders, or hirsutism. Treatment of hirsutism involves administration of oral contraceptive pills and antiandrogens. Clomiphene citrate, dexamethazone, gonadotropin and aromatase inhibitors are used in the treatment of ovulatory disorders. Gonadotropin-releasing hormone agonist plays a major role in IVF treatment as well as in superovulation. There are several insulin-sensitizing agents available to reduce insulin levels, and the most commonly used for women with PCOS is metformin. Metformin has replaced the surgical treatment of PCOS with ovarian drilling. Metformin improves insulin resistance and hyperandrogenism, decreases serum lipids, and improves glucose homeostasis.