Polycystic ovary syndrome (PCOS) is a common disorder. Its prevalence is 5 to 10% in women of reproductive age. PCOS is associated with hyperinsulinism and insulin resistance. The pathophysiological situations has lead many authors to study the action of insulin-sensitizing agents on menses, ovulation rate, and pregnancy in patients with PCOS. Metformin (a member of the biguanide family), is used for treatment of type II diabetes mellitus in obese patients. Although metformin restores cyclic pituitary- gonadal function and improves fertility, it can decrease levels of androgen and LH and increase levels of SHBG in women with PCOS. Trooglitazone (a member of the thiazolidinedione family) has been withdrawn from use because of its liver toxicity. Troglitazone improves ovulation and hisrsutism in women with PCOS without change in body mass index. Other similar drugs with less liver toxicity may be useful for the treatment of PCOS. D-chiro-inositol is a mediator of insulin action and improves ovulatory cycles. Most of the studies reported have not been randomized but the results appear to be quite promising. These drugs may provide a substantial advance in the treatment of women with polycystic ovary syndrome.