Background: Human Endometrium is a dynamic tissue during the menstrual cycle can be influenced by ovarian hormones. This layer is the main responsible for the successful implantation of the embryo is. The main factors is affect in the success. One of the most important factors that is endometrial thickness. The purpose of this study was to evaluate of the endometrial thickness under the influence of hormones that stimulate ovulation and progesterone.Methods: In the study, thirty adult female mice were divided into 3 groups as: control, gonadotropin and gonadotropin+progesterone. In 2 experimental groups the mice received 7.5 I.U HMG and later HCG. Then every two female mice with one male mouse put in one cage for fertilization. In groups 1 mg/kg gonadotropin+progesterone, progesterone administrated in 24, 48, 72 hours interval, after HMG injection. Ninety six hours after HMG injection, the mice in 3 groups were sacrificed and their uterine specimens were prepared for light microscopic studies.Findings: According to studies carried out with an optical microscope and using the software Motic Image Plus 3.2, endometrial thickness in Mean±SD was 358.05±15.35 mm in control group, 389.84±12.46 mm in gonadotropin group and 381.64±13.03 mm in gonadotropin+progesterone. Significant difference between the control group and gonadotropin group and too between the control group and gonadotropin+progesterone were not also observed. Also, the endometrial thickness in all groups were not significantly deferent from each other (P<0.05 for all of the comparisons).Conclusion: Using ovarian stimulation, followed by progesterone injection would not modify the endometrial thickness of mouse endometrium.