In the present study 144 adult albino rats were divided into:control group, three estrogen treated groups (with differentdoses) and orchidectomy group, for each group examinationunder light microscope, electron microscope as well asimmunohistology for estrogen receptors was done. Theexamination revealed a direct effect of estrogen on theprostate mainly in form of hyperplasia, inflammatoryinfiltration and dysplasia. It also revealed the presence ofestrogen receptors in prostate.