The review is considered morpho-functional and molecular mechanisms of development and aging of spleen. The immune system and it central organ – thymus had mach risk of aging involution. At this cause the part of thymic function delegated to spleen, which had not very strong involutive changes. There more, functional activity of spleen at aging can be repared with halping of peptide bioregulators. Thus, a review of data for the development and age involution of the spleen showed that the said body's immune system is less susceptible to ditrofii compared with the thymus. Furthermore, the structure and function of the spleen can be partially restored by the action of peptide bioregulators and the aging of the immune system with age, the spleen becomes one of the most important centers of immunogenesis.