Since the uterine is a sensitive tissue to steroid hormones, the aim of the present study was to investigate the effects of 17β-estradiol (E2) and progesterone (P4) alone or in combination on morphological and morphometrically parameters of ovariectomized mouse uterus.Adult virgin female mice (8-10 weeks old)were ovariectomized and treated with E2, P4, E2 followed by P4 and the oil vehicle alone for 5-days period. Uterine tissue was removed, and processed for histology assessment. The total uterine diameter were significantly higher (P < 0.05) following E2 treatment and Maximum diameter of uterine lumen, myometrium and endometrium were recorded after this treatment regimen. Sequential treatment with oestradiol and then progesterone caused both mitotic activity and cell degeneration. P4 treatment induced signs of active secretion in the endometrium glands and symptoms of degeneration and cell death. Estradiol treatment induced growth of uterine tissue. Subsequent treatment with progesterone stimulated uterine tissues to reach maximum size and maturity which is necessary to modify the uterus in preparation for pregnancy.