The article discusses the main issues related to the organization of reference services in university libraries all over the world in the framework of the traditional reference bureau and virtual reference service. The implementation of the concept of digital reference service requires high professionalism, expert knowledge of digital tools and methods of working with them on the part of the staff of reference services. The development of information technologies changes the format of communication between the bibliographer and the user. Traditional reference services are complemented by specialized research assistance carried out in accordance with research practices of universities. The provision of real-time and deferred virtual reference services, digital transformation of libraries, and the involvement of catboats with artificial intelligence in reference services are current issues in library theory and practice. The turning point in the evolution of reference services has been the university libraries strategic initiative for online learning and additional professional education. Due to the increasing educational mission of university libraries in the professional library community, the role of information curator that the reference librarian can assume is being actively discussed. Reference librarians, alongside with other information professionals, shape the library’s research and educational space. The article bases on the analysis of publications in foreign professional periodicals.