The review is considered morphofunctional and molecular mechanisms of development and aging of spleen. The age increases the risk of autoimmune and endocrine disorders, infectious diseases and cancer. It is known that the immune system, and in particular, its central body - the thymus, the most susceptible age involution. With the tie with that part of the functions of the thymus in aging is delegated to the spleen, less prone to age-related changes. Additionally, the functional activity of the spleen of aging can be reduced under the action of peptide bioregulators. In this review we analyzed the data for the development of age-related changes and the spleen from the point of view of immunology. Thus, review of data on the development and age involution of spleen showed that this organ of the immune system is less susceptible to degeneration compared with the thymus. Furthermore, the structure and function of the spleen could be partially restored by the action of peptide bioregulators.