Objective Gonadotropins are generally used in animals and humans to stimulate ovulation and increase the number of available oocytes for techniques such as in vitro fertilization. Ovulation-inducing drugs are used to achieve multiple oocytes in one cycle, thereby increasing the chances of pregnancy in patients with infertility. The aim of this study was to evaluate the effect of gonadotropins on stimulation of ovulation and their inductive role on the growth and development of follicles in the ovary. Methods To determine the effect of human chronic gonadotrophin (HCG) and pregnant mare serum gonadotrophin (PMSG) on ovary, this study used 20 rats that were randomly divided to experimental and control groups. Rats were subsequently euthanized 48 h after injection and the ovaries were fixed and stained with H&E. Data were analyzed with Tukey's multiple comparisons with one-way ANOVA test in GraphPad Prism software. Result Our analysis demonstrated that HCG and PMSG hormones will significantly increase the number of stimulated oocyte in the ovary but it does not have any significant role on the ovary weight and volume (P < 0.05). Conclusion This study's results confirmed the inductive role of PMSG and HCG hormones on folliculogenesis.