Background: In this study, an attempt was made to comparethe two stimulation protocols of GnRH agonist flare-up (F) andmicrodose GnRH agonist flare-up (MF), used in patients whohad a poor response to intracytoplasmic sperm injection cycle(ICSI).Methods and Materials: In this randomized controlled trialstudy, which was conducted between September ۲۰۰۸ and May۲۰۱۴, a total of ۱۳۱ poor responder patients who underwentintracytoplasmic sperm injection cycles were included. Patientswere excluded from the study if they had only one ovary, myoma≥ ۶ cm, azospermic partner, tumor or cyst>۱۳mm, age>۴۲. Patients were randomly assigned to one of the two groups of MF which required the administration of buserelin at ۸۰ μg,sc (n=۶۶) and F protocol which required the administration ofbuserelin at ۵۰۰ μg, sc (n=۶۵). The primary outcome measurewere clinical pregnancy and live birth rates. Statistical analysiswas performed using SPSS software. In all tests, the significancelevel was considered less than ۰.۰۵.Results: Both groups were comparable in regards to mean age,body mass index, type of infertility, infertility duration, basalhormone levels, gonadotropin type and history of surgery. Likewise,there were no significant differences with respect to cyclecancellation, the mean number of dominant follicles, achievedoocytes and MII oocytes, hormone levels on hCG day, numberand quality of embryos transferred between groups. Additionally,number of stimulation days and endometrial thicknesswere significantly (P=۰۳۲ and P=۰.۰۰۱ retrospectively) andgonadotropin dose was insignificantly (P=۰۷۵) higher in MFgroup than F group. No statistically significant differences werefound in rates of clinical pregnancy, implantation and miscarriagewith MF regimen compared with F protocol. Live birthwas significantly (P=۰۳۶) higher in MF group than F group.Conclusion: In conclusion, MF protocol seems to be superiorto the F protocol but requires a higher dose of gonadotropinsand longer duration of stimulation. Although, this would obviouslyresult in differences in costs of money, this improvementis of probable clinical importance. Further prospective clinicaltrials on this topic are recommended.