Background: The complications of IUDs are abnormal uterine bleeding, dysmenorrhea, expulsion of the IUD or perforation of the uterus. Due to these complications, 5 to 15 percent of women will stop using the IUD during one year. The most common complication of using IUDs is bleeding that is the cause of 15 to 30 percent of the rejection and exclusion of copper IUDs by the users. Except for progesterone IUDs, all IUDs can lead 50-100 percent increase the amount of menstrual blood than before the insertion. Purpose: To compare between two types of copper IUDs different in shape and size Cu375 & Cu380Ag regarding bleeding pattern. Patients and Methods: This is a randomized controlled clinical trial. The study was conducted at Family Planning Outpatient Clinic at Department of Obstetrics & Gynecology at Ain Shams Maternity Hospital on 220 patients divided into two groups with insignificant differences between two groups as regard age (p-value 0.934). Results: 110 participants recruited in each group. In group A, drop out after 1month was 6 women and only 70 women had subjective changes in bleeding pattern. After 1year, drop out was 8 women. In group B, drop out after 1month was 4 women and only 79 women had subjective changes in bleeding pattern. After 1year, drop out was 5 women. Conclusion: One of the most common complications of IUD users is bleeding. These complications vary in the different types of IUDs. The results of this study showed that the use of the IUD ML CU 375 causes a significant decrease in the rate of bleeding.