Intrauterine insemination is a procedure that involves the deposition of a processed semen sample in the uterine cavity, overcoming natural barriers to sperm ascent in the female reproductive tract. Integrin are able to promote endometrium decidualization, maintain quiescent condition of the uterus, prevent uterine contraction before implantation, benefit embryo adhesion and nidation and influence polarity of endometrial glandular epithelium. Hyaluronic acid is a glycosaminoglycan found all over human bodies. Intra-vaginal HA pessaries used to improve implantation in ICSI cycle by increasing endometrial vascularity and by increasing adhesion between trophoblast and epithelial layer of endometrium. This study for the first time used HA pessaries to improve ER in IUI cycle. To evaluate the effect of using intravaginal hyaluronic acid on endometrial receptivity by assessing serum integrin level as a (biomarker of implantation) and assessing role of vaginal HA in improving pregnancy rate in infertile couples undergoing IUI treatment. The study included 49 infertile couples whom were selected randomly from those attending the High Institute of Infertility Diagnosis and Assisted Reproductive Technologies Al-Nahrain University. After conducting full assessment, all couples entered intrauterine insemination cycle; they divided into two group A (n27) and group B (n 22). Women in-group A receive HA pessaries 5mg once daily from cycle day 7 until day 21. Blood samples were taken to measure integrin level on CD2 and on day of IUI. Endometrial receptivity markers (ITG) used as a comparative parameter among selected groups. Pregnancy outcome assessed 14 days after IUI, also used as a comparative parameter among selected groups. There was no significant difference in integrin levels between study and control groups at cycle day 2 and at day of IUI with p=0.114 and p=0.407 respectively. However, serum ITG level increase in day of IUI in study group and not affected in control group. We did simple comparison of serum ITG between pregnant and non-pregnant women, there was non-significant difference, but pregnant women have higher serum integrin levels compared to non-pregnant women. Use of intravaginal HA during intrauterine insemination (IUI) cycle improves ER and pregnancy rates and this proved by its positive effect on serum ITG levels. However, the increase in pregnancy rate was statistically non-significant; this might be due to small sample size.