The scientific data of the last years shows that increased level of the testosterone in the blood is not a main factor of the development of benign prostatic hyperplasia (BPH), though the exogenous supply in big doses is used for the induction of BPH in the experimental animals. Moreover the growth of the frequency of the BPH is linked to the low level of the testosterone, which is a part of the ageing and a consequence of the pathological conditions, such as metabolic syndrome or diabetes. The increased conversion into dihydrotestosterone is a compensatory way in the state of androgen deficiency, which is more active and can induce cell proliferation in prostate due to 5-alpha-reductase activation. The increase in the activity of this enzyme could be linked with the alterations in the blood supply to the prostate and consequent tissue hypoxia. Importantly, the main factor leading to BPH is the increased transformation of the testosterone into the 17-beta-estradiol, as a result of which a increased proportion of the testosterone/estradiole could be seen, which is typical for the patients with BPH. Nevertheless, the action of the estrogens in terms of the proliferation of the prostate cells is controversial and depends on the proportion of the alpha- and beta-receptors activity and androgen/estrogen proportion. The patients with the metabolic syndrome and androgen deficiency and disturbances of the carbohydrates metabolism have another important factor, which leads to the development of the BPH – hyperproduction of the insulin and insulin-like growth factor.