BACKGROUND:Gonadotrophin-releasing hormone (GnRH) agonist has been proposed as an alternative drug to human chorionic Gonadotropin (hCG) for triggering. The purpose of this study to analyze the effects of three types of trigger hCG, GnRH-a or combine of them (dual) on quality of oocyte and embryoand ovarian hyperstimulation syndrome (OHSS)in the ICSI cycle. METHODS:A prospective case control study was conducted on 320 women who referred to Milad, IVF Center, Mashhad, Iran, between May 2016 and June 2019. All patients underwent antagonist protocol and were classified according to the type of trigger in three groups, 118 patients in the GnRH-agroup, 49 patients in the hCG group, and 153in dualgroup. The oocytes were retrieved after 36 hours of injection of the trigger. The outcome measures were the number ofmetaphase I,metaphase II oocyte, Germinal vesicle (GV) oocytes, high-quality embryo and rate of OHSS.RESULTS:Three groups were not significantly different in terms of the proportion of retrieved oocytes, the number of embryos, M I oocyte, M II oocyte, and the number of GV oocytes. The quality of embryos between the three groups was difference significantly (p<.05). In comparison to dual and GnRH-a group trigger, women who received hCG group had a higher number of OHSS, and the number of severe OHSS in dual trigger was higher than GnRH-a vs and hCG groups.CONCLUSIONS: GnRH agonist alone and dual trigger (hCG, GnRHagonist) can be as effective as hCG trigger. GnRH agonist is preferable in high risk patient. Therefore, it should be used according to the patient’s condition.