Androgens regulate development and functional maturation of the prostate. A lack of androgens at puberty impairs normal prostate growth and causes regression and atrophy of the gland in adults. Orchidectomy or indirect androgen suppression by hypophysectomy or administration of oestrogens reduces prostatic weight and secretion. As far as prostatic cancer is concerned, significant improvement occurs in the clinical conditions of patients affected by advanced neoplasia subjected to castration or oestrogen administration. Recently, other endocrine manipulations have been proposed, but the response to these treatments strictly depends on the composition of the neoplastic population. Prostatic cancer consists of cells that are sensitive to or dependent on hormones and others that are hormone-independent. Biological activity of hormones, particularly androgens, is mediated via intracellular receptors, which are not easy to measure in prostatic tissue. Androgen receptor level can be modulated in prostatic cancer cells by natural interferon-beta, opening new perspectives in the therapy of prostatic cancer.