Endometrial reactions after IUD insertion for a long period ranging from 7 to 9 years were studied in cases selected from family planning clinics in Cairo. 71 endometrial biopsies were taken from the women who were wearing Lippes loops C. Chronic endometritis was present in 54.95% of the cases. Stromal hemorrhage was found in 45.07% of the cases, and cystic glandular hyperplasia was present in 23.84%. Stromal fibrosis, which was found in 12.12% of the cases, was marked and generalized. The general incidence of abnormal findings with the long-term use of the device was 65%. It is concluded that the presence of an IUD for several years may lead through its mechanical and possible local hormonal action to various pathological changes indicating endometrial irritation and activity. It is advised that women wearing the IUD be subjected to periodic pelvic examinations with routine Papanicolaou's smear and even endometrial biopsy if needed. Removal of the device with a time of rest is recommended to avoid long-term use with its possible untoward endometrial changes.