The subject of the literature review are pathogenetic mechanisms, underlying aging and related basic diseases. Data on the relation between physiological и chronological age are given, questions physiological and premature aging are considered, current theories of aging are discussed. The author stresses the importance of laboratory research methods, which, owing to their ability to quantitatively express the value of a particular parameter, can detect changes of parameters, related to functional and regulatory characteristics of organs and systems in elderly people, and hence allow determination of individual physiological age and main pathogenetic mechanisms of premature aging.