OBJECTIVE To compare GnRH agonists and antagonists in oocyte-donation IVF treatment cycles by a systematic review and meta-analysis of trials. DESIGN Systematic review and meta-analysis of randomized clinical trials (RCT). Systematic literature searches were conducted, and all randomized trials that compared GnRH agonists with antagonists in oocyte-donation IVF treatment cycles were included. Study selection, quality appraisal, and data extractions were performed independently and in duplicate. SETTING Tertiary fertility center. PATIENT(S) A total of 1,024 oocyte donors treated in eight RCTs. INTERVENTION(S) Comparison of GnRH agonists versus antagonists in oocyte-donation IVF treatment. MAIN OUTCOME MEASURE(S) Ongoing pregnancy, oocytes retrieved, duration of stimulation, gonadotropin consumption, and ovarian hyperstimulation syndrome incidence (OHSS) per randomized oocyte donor. RESULT(S) Meta-analysis of these studies showed no significant difference in ongoing pregnancy rate between the GnRH agonists and antagonists (risk ratio [RR] 1.15, 95% confidence interval [CI] 0.97 to 1.36). The duration of stimulation was significantly lower with the GnRH antagonist protocol (weighed mean difference [WMD] -0.90 days, 95% CI -1.61 to -0.20). No significant differences were observed in the number of oocytes retrieved (WMD -0.60, 95% CI -2.26 to +1.07), gonadotropin consumption (WMD -264 IU, 95% CI -682 to +154), or OHSS incidence (RR 0.62, 95% CI 0.18 to 2.15). CONCLUSION(S) No significant differences were observed in ongoing pregnancy rate or the number of retrieved oocytes after donor stimulation with GnRH agonist or antagonist protocols.