Objective: We aimed to compare the patient groups who underwent ovulation induction and intrauterine insemination (IUI) by using clomiphene citrate (CC), aromatase inhibitor (letrozole), and letrozole together with CC in the treatment of patients with unexplained primary infertility. Ma- terials and Methods: This study was conducted on 90 primary infertile couples who were diagnosed with unexplained infertility and applied with the desire to have children. The patients were divided into 3 groups according to the agent to be used in ovulation induction. 1st group; CC and letrozole; Group 2 was treated with letrozole only, and Group 3 was treated with CC only. Ovulation was triggered with 6500 IU choriogona- dotropin-alpha in patients who have dominant follicles. IUI procedure was performed approximately 36-38 hours after ovulation.During the fol- low-up, pregnancies and fetal heartbeat were recorded. Results: There was no significant difference in the amount of estradiol increase and endometrial thickness measured on the day of IUI between the groups. At the time of ovulation induction, the number of follicles between 14-18 mm was 2 in the first group and 1 in the other two groups, but when the number of dominant follicles (>18 mm) was examined, there was no sta- tistical difference between the groups. There were no statistical differences between groups in terms of pregnancy rates.Conclusion: In patients who underwent ovulation induction and IUI with CC and letrozole combined, CC alone and letrozole alone, no superiority was observed between the groups in terms of pregnancy rates.