To compare the ovarian responses after administration of two recombinant follicle-stimulating hormone (r-FSH) preparations under gonadotropin-releasing hormone (GnRH) analogue downregulation, we conducted a phase 3, randomized, multicenter, assessor-blind, active-controlled, parallel group study. The primary outcome was the number of oocytes retrieved. The secondary outcomes included total dose and duration of r-FSH administered, oocyte quality, blood estradiol levels, follicular development, fertilization rates, implantation rates, and pregnancy rates (biochemical, clinical, and ongoing). A total of 451 patients with infertility were randomized to receive either Follitrope™ Prefilled Syringe or Gonal-F® Pen for ovarian stimulation. The mean number of oocytes retrieved was 14.9 in the FollitropeTM Prefilled Syringe group, and 12.8 in the Gonal-F® Pen group. The 95% confidence interval in the oocyte number difference between the groups was [–0.1, 4.2], demonstrating that FollitropeTM Prefilled Syringe was not inferior to Gonal-F® Pen. The clinical pregnancy rates (FollitropeTM Prefilled Syringe vs. Gonal-F® Pen: 55.4% vs. 51.9%) and ongoing pregnancy rates (44.1% vs. 43.0%) were similar between the groups. No clinically significant adverse events were observed in either group. In summary, our study indicates that FollitropeTM Prefilled Syringe is safe and efficacious for ovarian stimulation.