Dynamic changes in the modern society necessarily initiated changes of existing basic tasks of the University and other institutions of higher education. It was also necessary to find a new paradigm coordinated with the information society's basic characteristics and requests, and to find a new paradigm of a modern university library. The article points at new roles and tasks of modern university libraries: university library as active partner in learning and creating knowledge; university libraries' role in forming of university and national information infrastructure; university library and/or digital library; collection development, electronic sources access, hybrid library; university libraries' role in open distance learning programs and life long learning programs etc. The article is based on Croatian experiences and conditions, especially on the situation at the Josip Juraj Strossmayer University in Osijek, and brings experiences in University library system development of the Josip Juraj Strossmayer University in Osijek and in the project "Union catalogue of the Josip Juraj Strossmayer University in Osijek".