Background: The intra uterine insemination (IUI) still an easy, simple and effective method to overcome the infertility that resulted from different causes. Although the equipments and methods of assisted reproductive technologies (ART) were highly developed, the percentage of successful IUI live-birth not exceed 20-30%. Objective: The present study was aimed to elucidated the cut off values of in vitro sperm preparation technique, follicular number and size, endometrial thickness and hormonal profile that lead to successful pregnancy rate (PR)following IUI. Materials and Methods: In retrospective study, one hundred cases of infertile couples were in who were became pregnant following IUI at the Institute of Infertility Diagnosis and Assisted Reproductive Technologies, through the period from January 2007 to January 2010. Depending on the results of retrospective study, IUI was achieved for 100 infertile patients between August 2010and June 2011. The mean of significant prognostic variables were measured in both studies namely: age, type of infertility, type of sperm activation techniques, the protocol of ovulation induction medicine, the mean of hormonal status of Luteinizing Hormone (LH), Estradiol(E2), and number with diameter of follicles, endometrial thickness a cycle day before hCG injection. Results: The protocol of ovulation induction in IUI cycles by using clomiphene citrate(CC) and recombinant gonadotropin (rFSH) was significantly(p<0.05) improve the IUI results compared to CC alone or CC with PergonalS. The mean values obtained by ultrasonography namely; two follicles, and dominant follicle of 19.5mm in size with endometrium thickness of >9.5mm were gave significantly successful IUI outcome compared to other values. In prospective study similar results were obtained, therefore the overall pregnancy rate was 37% per cycle. Conclusion: The calculated data of successful IUI outcome from retrospective study gave a best pregnancy rate in prospective study which was 37%. Consequently, these results can be considered as guideline for physician who interest in assisted reproduction to have a success in IUI.