The aim of the paper is to present the changing role of public libraries on the example of the University of Warsaw Library. The 18th century was particularly important for the history of public libraries. Then their intensive development as publicly accessible institutions took place. The next century brought the strengthening of the idea of public libraries as centers of culture and education. At the same time, it was a difficult time for libraries in Poland. As a result of the partitions, they were deprived of the protection of the Polish state, and their activities focused on protecting the national heritage. In such circumstances, in 1817 the University of Warsaw Library was established. In fact, from the beginning of its existence, it combined the functions of a university library and a public library, although since then the detailed mode and main function of its activity have changed many times. Nowadays, electronic resources and Internet sources are gaining more and more popularity among library users, and libraries are treated more as a space for personal work than as a place of access to collections.