A theory of aging based on the principles of the kinetics of chemical reactions and the rules of natural selection of organisms is proposed. The theory is based on a hypothesis that the biochemical processes in the organism can be described in the terms of chemical reaction kinetics. The evolutionary process of organisms is determined by the goal of continuing life, and the natural selection forced organisms to develop in an optimized way for survival and reproduction, after which any further development of the organisms did not matter for natural selection and therefore was not regulated by it. Accordingly, the ongoing biochemical processes in the organism after giving birth were not stabilised and continued casual, which, in the case of complex systems of biochemical processes, led to imbalances and biochemical processes that did not contribute to health in the organism, resulting in aging. Based on this view, it is necessary to look for the key biochemical processes that regulate the vital activity of the organism. Balancing of these processes in the period after giving birth can artificially lead to the stabilization of the kinetics of biochemical reactions, and consequently, the continuation of life almost indefinitely.