Rodents were used as model to detect the effect of developmental estrogenization in the first 1-5 days post-natal (neonatal period) on the prostate. The mechanisms behind the effect were approached. Male rats were injected at PND 1,3 and 5 by 5 ml of folone (estradiol benzoate) (estrogenized subgroups) and sesame oil (control subgroups). Animals were sacrificed on PND 6, 10, 15 and 30 accordingly male rats were divided into four groups. Sections were stained by Hematoxylin and Eosin, Masson Trichrome, immunohistochemical stains for laminin and androgen receptors. Those of group II were stained for PCNA. Also tissues from group II were processed for ultrastructural study. Results revealed presence of delayed development in estrogenized animals and the presence of epithelial hyperplasia, interstitial lymphocytic infiltration and increased stromal amount.The ducts and acini in estrogenized animals were surrounded by a laminin free zone which was found to be formed of several layers of fibroblasts. AR immunostain was gradually decreased in the estrogenized animals. It was concluded that the thick layer of fibroblasts interfere with the epithelial and smooth muscle interaction resulting in adverse histological changes as the animal aged.