The majority of women with anovulation or oligoovulation due to polycystic ovary syndrome (PCOS) often have clinical and/or biochemical evidence of hyperandrogenism. This chapter describes the treatment with clomiphene citrate (CC), aromatase inhibitors (AIs), gonadotropins, and metformin followed by a discussion on the management of women with PCOS undergoing in vitro fertilization (IVF). It deals with the combined treatment of clomiphene with metformin. In women with PCOS, metformin is said to lower fasting insulin concentrations but also probably acts directly on theca cells and attenuates androgen production. The aim of the chronic low-dose step-up protocol is to obtain the ovulation of a single follicle. While results of IVF for women with PCOS are generally satisfactory compared with those with normal ovaries, ovarian stimulation protocols must be adapted accordingly to avoid the major pitfall of ovarian hyperstimulation syndrome (OHSS) in these women.