Based on the authors' own data and a review of current literature, the role of vasopressin (VP) in the mechanisms of age-related changes, development of stress-reactions and pathology onset is discussed. In aging, the VP concentration in blood and cerebrospinal fluid increased, its level in pituitary rose and that in hypothalamus fell. Under stress (emotional-painful stress, water deprivation) the potential capabilities of the VP-ergic system decreased with age. The role of weakening central monoaminergic influences with aging in changing the intensity of VP secretion is discussed. The results of an ultrastructural analysis and karyometry of the neurosecretory cells testify to an adequate preservation of their protein-synthesizing system and a high level of secretory activity in old age.