The human endometrium is a complex, multicellular tissue that is regulated by steroid hormones (estrogens, progesterone, androgens, and glucocorticoids) and has different characteristics in the various phases of the menstrual cycle. HCG plays a major role in endometrial receptivity via modulation of the production of various cytokines and chemokines. Aim of the Work:The study aimed to show the effect of intrauterine injection of Human Chorionic Gonadotropin (HCG) on the day of ovum pickup in patients with a history of one or two failed Intra Cytoplasmic Sperm injections (ICSI). Patients, and Methods: A sample of 110 patients was obtained, half of them were candidates for intrauterine injection of 500 units of HCG immediately after ovum retrieval during the mock, while the other half were controls. All patients underwent controlled ovarian stimulation using the long protocol. The study was conducted at the Assisted reproduction unit of