Women affected with polycystic ovarian syndrome (PCOS) are the most difficult patients for a successful treatment with controlled ovarian hyper stimulation (COH). Their multiple and small antral follicles may be either resistant or highly sensitive to gonadotropin stimulation. Numerous controversies exist concerning the best protocols for folliculogenesis in PCOS patients. One new approach for ovarian stimulation which has been reported in some previous studies is adding low-dose human chorionic gonadotropin (hCG) in the late follicular phase. The role of LH in sensitizing antral follicles to FSH is unclear. LH is required for normal hormone production and normal oocyte and embryo development but follicular responses to LH may depend upon the stage of development. Low-dose hCG has a longer half-life and lower cost compared to recombinant LH. In addition full development of large follicles adequate ovarian hormonal level oocyte maturation avoidance of premature LH surge and increment of pregnancy have been demonstrated by adding of low-dose hCG in late folliculogenesis. Recently Filicori et al showed that the completion of folliculogenesis could be achieved with the administration of low-dose human chorionic gonadotropin (hCG) in controlled ovarian hyper stimulation after 7 days of FSH-only priming. They have also reported a similar pregnancy rate with the use of this stimulation protocol in in vitro fertilization (IVF) with intracytophasmic sperm injection (ICSI). Traditionally the role of LH in the control of the menstrual cycle was believed to be limited to stimulating theca cell androgen production triggering ovulation and support of the corpus luteum. However the physiologic selection of the dominant follicle in spontaneous menstrual cycles is now believed to be the result from the expression of LH receptors in the more mature ovarian follicles (>10 mm in diameter). Ashrafi et al in their recent RCT compared the efficacy of two regimens of low-dose hCG (100 IU/ day or 200 IU/ day for folliculogenesis of PCOS women. These authors could not find any significant differences about stimulation duration and mean number of mature oocytes. However immature oocytes were significantly lower in patients who received 100 IU hCG (group B). Study groups (groups B C) also had lower gonadotropin consumption than the control group. Fertilization implantation and pregnancy rates were similar amongst the groups. In summary it seems that this new ovarian stimulation protocol permits follicles and oocytes to fully develop; helps generate top-quality embryos avoids premature ovulation establishes clinical pregnancies reduces administration of recombinant hFSH minimizes costs and does not increase the chances of OHSS.