Seventy adult female albino rats were used in this study. The rats were divided into four groups, which were subjected to three different doses of tamoxifen or ovariectomy. The rats were sacrificed and the uteri were removed, examined and prepared for histological examination. The uteri of tamoxifen treated groups showed endometrial and glandular hyperplasia with detection of apoptotic changes in the form of pyknosis, vesicular nuclei and vaculations while in ovariectomized group the uteri showed atrophy of both glands and lining endometrium.