Background:The natural cycle (unstimulated cycle) was used in first IVF trial which give birth of a life baby. However, it was soon recognized that the success rate of IVF in natural cycles was low, this may be due to the low number of oocytes retrieved. Ovarian stimulation using urinary gonadotropins was applied to deal with this problem, resulting in a significant increase in both the number of eggs retrieved, as well as the success rate of IVF. But in the same time the using of stimulation drugs may negatively affect oocyte and embryo quality which could diagnosed by using non invasive procedure like measurement of miRNA- 320 in follicular fluid. Aim of study:To compare the effect of stimulation protocol on ICSI outcome using miRNA- 320 that reflects the embryo quality. Materials and method:This comparative study was done on the embryos of seventy one infertile females who were undergoing Intracytoplasmic sperm injection (ICSI) treatment regardless to the presence or absence of previous trials. These patients were divided into two groups, 45 of them treated with agonist protocol and other 26 patients treated with antagonist protocol. Of the 71 oocytes, there were eight immature oocytes (3 at germinal vesicle (GV) stage, 5 at metaphase I (MI) stage) and three abnormal oocytes, and these were excluded from the following ICSI treatment. Measurement of follicular fluid mi-RNA 320 (which is known biomarker of embryo quality) was done by PCR. Results:The statistical analysis showed no significant correlation between miRNA- 320 levels in follicular fluid and age, BMI, number of dominant follicles, number of oocytes retrieved, number of metaphase I, metaphase II, germinal vesicle, abnormal oocytes and number of fertilized oocytes (2PN). The comparison between miRNA 320 levels in good and bad quality embryos showed highly significant (p<0.001) difference but no significant difference (p>0.05) was found between the different stimulation protocols. Conclusions:The stimulation protocol does not affect the level of miRNA which is molecular marker of embryo quality.