Polycystic ovary syndrome (PCOS) affects 5-10% of women in childbearing age. Hyperinsulinemia contributes to chronic anovulation commonly encountered in women with PCOS. The first choice therapy is clomiphene citrate (CC). In CC resistant cases, the American College of Obstetrics and Gynecology (ACOG) recommends the use of insulin sensitizer metformin. Other insulin sensitizing agents include rosiglitazone and pioglitazone. Pioglitazone is said to improve fertility and ovulation in patients with PCOS.CC may be associated with poor endometrial thickening due to its antiestrogenic effect. Letrozole may improve this condition. In this study we will compare the effect of combined letrozole-metformin with that of combined letrozole-pioglitazone in ovulation induction in CC-resistant PCOS women