 Letrozole has been tried for ovarian stimulation for assisted reproduction. With the concept of mild stimulation in IVF to improve implantation rate, letrozole is a potential agent. Letrozole has two potential uses in IVF: First, where it is used in the follicular phase usually with FSHhuman menopausal gonadotropin HMG for ovulation induction; second, it has also been used in luteal phase of stimulated IVF cycle and to reduce circulating E2 levels; thus, potentially reducing ovarian hyperstimulation syndrome OHSS risk. 