This study aimed to improve the uterine receptivity and luteal function following timed artificial insemination (TAI) by using gonadotropin releasing hormone (GnRH) and human chorionic gonadotropin (hCG), and to evaluate the effects of these treatments on pregnancy rates in dairy cows. In experiment I, dairy cows (n=141) were subjected to TAI protocol 50 days after calving. The cows were randomly divided into the control group (n=52), GnRH group (n=31, given 100 μg GnRH each) and hCG group (n=58, given 1500 IU hCG each) five days after TAI to study their effects on the blood progesterone levels and the pregnancy rates. In experiment II, bovine endometrial epithelial cells were cultured and treated with GnRH and hCG to study effects of these hormones on expression of specific genes including Toll-like receptor 4 (TLR-4), Nuclear factor-kappa B (NF-κB), Leukemia inhibitory factor (LIF) and Interleukin-1 (IL-1). The results showed that the injection of GnRH and hCG 5 days after AI significantly increased blood progesterone concentrations. However, differences in pregnancy rates between the cows of three groups (51.61, 53.45 & 36.54% in GnRH, hCG and control groups, respectively) were non-significant. PGF2a secreted by hCG-treated endometrial cells was significantly higher than that of the GnRH-treated cells and the control group, and the difference between the latter two groups was non-significant. GnRH and hCG treatment inhibited TLR-4 and NF-κB signaling pathways and promoted expression of LIF gene. In conclusion, the injection of GnRH and hCG 5 days after AI was beneficial to the function of the corpus luteum and uterine receptivity, although improvement in pregnancy rates was non-significant.