OBJECTIVE To compare pregnancy rates and the incidence of ovarian hyperstimulation syndrome (OHSS) in donor stimulation cycles where final maturation of oocytes was induced with recombinant hCG or GnRH agonist. METHODS Retrospective, cohort study. METHODS Private infertility clinic. METHODS A total of 1171 egg donors performing 2077 stimulation cycles. METHODS Controlled ovarian hyperstimulation of egg donors with GnRH antagonist protocol triggered with recombinant hCG (rhCG; 250 microg) or GnRH agonist (triptorelin 0.2 mg) based on the physician's decision. METHODS Proportion of mature and fertilized oocytes per donor cycle; clinical, ongoing pregnancy and implantation rate in recipients; and incidence of moderate/severe OHSS in oocyte donors. RESULTS The proportion of mature oocytes was comparable, whereas the difference in the fertilization rate reached statistical significance (65% vs. 69%). No significant differences were observed in the implantation rate or clinical and ongoing pregnancy rates per ET. The incidence of moderate/severe OHSS was 1.26% (13/1031; 95% confidence interval [CI], 0.74-2.15) and 0% (0/1046; 95% CI, 0.00-0.37) in the rhCG and GnRH agonist groups, respectively. CONCLUSIONS Recipient outcome was not significantly different when using oocytes from GnRH antagonist-treated donor cycles triggered with hCG or GnRH agonist. However, GnRH agonist triggering was associated with a lower incidence of moderate/severe OHSS in egg donors.