Background: The purpose of present study was to evaluate the role of pre-ovulatory GnRH agonist therapy on IVF outcomes in GnRH antagonist cycles. Methods: In this prospective study we recruited 100 infertile women undergoing IVF cycles with GnRH antagonists. The patients were assigned to two groups: Group A (the study group, n=42) were assigned for receiving hCG+triptorelin for the final oocyte maturation and group B (the control group, n=58) were assigned for only hCG. The t-test, chi-square (2), and Fisher's exact test were used for data analysis. A p < 0.05 was taken as statistically significant. The results are presented by mean SD, and in percents (%). Results: LH levels significantly (p < 0.001) increased in the study group on the day of oocyte retrieval. All embryological parameters including the number of mature oocytes, fertilization and cleavage rates, number of high quality embryos and number of cases whose embryos were frozen were non-significantly higher in the study group. There were small but non-significant improvements in the clinical pregnancy, ongoing pregnancy, live birth and implantation rates in the study group. Conclusion: Administering a single dose of GnRH agonist before oocyte retrieval in antagonist cycles may be helpful in improving the pregnancy rate but the results need to be verified in a larger trials.