One of the primary task of the National Library of Serbia is to ensure and to provide the universal and permanent Accessibility to the Librarian Materials, preserved in its Holdings. On the other hand, during its direct usage, the original Material is being damaged, for that, it is indispensable to protect it. For the Project Team of the System for Conservation of the Library Materials, these two mutually contradictory demands emerged in first place the problem of choosing the media that is going to be used in the Preservation System. The Analysis of the available media, its endurance, and conveniences for usage has shown that the Hyibrid System is the optimal solution for the conservation and the usage of the Library Materials, since at the present knowledges, this system represents the juncture of the best features of the Microfilm (endurance and realibility) and the digital record (ease of search, access speed and accessibility from distance).