Since the discovery of prolactin, scientific and practical interest in it has been focused exclusively from the standpoint of female endocrinology and reproductology. At the same time, the physiology and pathophysiology of prolactin in men, due to the historically established interpretation of the functions of this hormone only as an endocrine regulator of the female reproductive system, have remained insufficiently studied for a long time. However, in recent decades, convincing scientific evidence has begun to accumulate that prolactin is just as important for men as for women. It has been shown that in both sexes prolactin not only exhibits important classical (reproductive) effects, but has a wide range of non-productive physiological functions in many organs and cells. In particular, to date, not only reproductive, but various hormonal-metabolic, psychosomatic, immune-inflammatory, sexual disorders caused by disorders of prolactin secretion (hypo- and hyperprolactinemia) have been described.The review article, based on the available modern literature, examines the general issues of endocrinology and physiology of prolactin in men, as well as the main andrological manifestations of disorders of its secretion by male reproduction, male sexual function and prostate gland.