Background and Aims: IUI is one of the most used methods to treat various forms of infertility. The aims were to compare the success rate of IUI with that of timed intercourse, review the methods used to time the IUI with ovulation, identify the factors to determine IUI outcome, compare the success rate of double IUI vs single IUI. Method: This is a cross-sectional prospective study conducted at a Private Fertility Centre, Chattogram, Bangladesh over a period of 40 months from 996 patients who underwent IUI. Variables such as age of women, cause of infertility, drugs used for COH, number of mature follicles, endometrial thickness post wash sperm count, type of IUI (single IUI and double IUI) were recorded and statistically analyzed. Results: The age for females and males were 18-41 and 23-52 respectively. The mean endometrial thickness was 8.9 mm ± 0.2 mm. Pregnancy rate for total motile sperm count less than 10 million was 7.2%. The successful conception rate for females were the age 28 was 9.6% compared to the whole group at 12%. Among 996 patients, 109 patients (10.94%) had successful conception. 209 patients (20.98%) underwent double IUI out of which 40 patients (19.14%) had a successful conception while 787 patients (79.01%) underwent single IUI out of which 69 patients (8.76%) had successful conception. Conclusion: IUI is currently a successful treatment modality for infertility especially as invasive treatment for couples with unexplained infertility, male factor infertility, anovulation, female less than 30 years of age. The numbers of motile sperms, appropriate endometrial thickness, have a remarkable impact on the outcome of IUI. Double IUI increases the success rate significantly. Acknowledgment: The authors are grateful to all who participated in the preparation of this manuscript.