Immunization represents the most cost-effective means to achieve the prevention of infectious diseases. Vaccines successfully protected humans from serioi, infections resulting in worldwide eradication of smallpox and regional elimination of poliomyelitis. New technologies continue to provide many effective biological products for disease control. Various techniques including recombinant DNA approaches, peptide synthesis chemistry, ami imniunotnodulation have been applied to the development of new vaccines and improvement of existing vaccines. These technologies have constructed avirulent and attenuated strains to be used as live vaccines, as well as provided more effective manufacturing methods to produce protein antigens, bacterial polysaccharides (PS) and PS-proteIn conjugate vaccines, Ailjuvsint is an agent added to biologies that augments specific imimme responses to antigens. Adjuvants can be divided into several classes including aluminuin salts, surface-active agents, bacterial derivatives and slow-release materials* Nonionic block copolymer as a multiple emulsion, and proteinoid microspheres were also developed for use in various vaccines. The ideal vaccine delivery system depends on the capabilities of the controlled delivery system to achieve optimum concentration of antigens, while maintaining vaccine stability under physiological conditions. Microspheres were used for controlled release of antigens whereas peptides of monoclonal antibodies were applied for enhancement of mucosal IgA antibody formation.