Abstract: Curettages were performed in 139 postmenopausal women before, and 6 months, 12 months and 36 months after Nylestriol （CEE3）therapy. It was found that CEEE₃ might induce endometrial proliferation and uterine breakthrough bieeding, and more so in women using 2mg of CEE₃ than in those using ling. The incidence of proliferation in our group was lower than in those women having conjungated estrogen therapy as reported in the literature. Ciliated cells were present in the proliferative endometrium after CEE₃. the success rate of obtaining endometrial curettings in women after 12 months’ therapy was not higher than alter 6 months. No curetting obtained 36 months after therapy may be explained by CEE₃ having a weaker effect on the endometrium and the regular additional doses of progestin postponing endometrial proliferation.