Objective: To compare leuprolide acetate to hCG as the trigger for final oocyte maturation in oocyte donor cycles. Design: Retrospective review. Setting: Academic IVF donor program. Patient(s): Thirty-two healthy oocyte donors aged 21-33 years with adequate ovarian reserve. Intervention(s): Donors were down-regulated with cetrorelix and received either leuprolide acetate (n = 12) or hCG (n = 20) for final oocyte maturation. Main Outcome Measure(S): Embryo number, embryo quality, fertilization, implantation, clinical pregnancy, and ovarian hyperstimulation syndrome rates. Result(S): The numbers of total oocytes (23 vs. 15), mature (metaphase 11) oocytes (22 vs. 13), embryos (15 vs. 10), and cryopreserved embryos (12 vs. 6) per treatment cycle were significantly greater in the leuprolide arm than in the hCG arm. Fertilization rates (73% vs. 78%), implantation rates (30% vs. 29%), and clinical pregnancy rates (40% vs. 50%) were not statistically different between the arms. There were no cases of ovarian hyperstimulation syndrome. Conclusion(S): Leuprolide acetate-triggered oocyte donor cycles yielded similar fertilization, implantation, and clinical pregnancy rates to hCG-triggered cycles. (Fertil Steril (R) 2010:93:374-8. (C)2010 by American Society for Reproductive Medicine.)