Purpose. For many decades, the Zagreb City Library network have offered numerous specific activities and services to their users in the music and audiovisual departments and collections. The aim of this paper is to identify and present the development path of the departments and collections (general regulations, organisation, criteria and guidelines for acquisition) that have led to the successful functioning of audiovisual departments and collections as parts of a library, but also as parts of the library network. The goal is also to ensure the availability of information for a wide range of users by continuously updating websites, and the implementation of other network resources for the purpose of improving the library services. Approach/methodology. In this paper, in addition to the historical overview (stating the year when each department was founded), the other data have been collected for all locations of audiovisual departments and collections, as well as the data on the size of their holdings within the Zagreb City Library's network. The statistics on the membership, the annual circulation and the current size of the library holdings, and the acquisition and borrowing of the audiovisual materials were also considered. Findings. The Zagreb City Library functions as one institution that includes a network of libraries, but the organization and development of audiovisual departments and collections have been adapted to the various local needs and are based on the concept of coordination rather than centralization. The head librarians of the collections develop their personal and common competences through the exchange of data, experiences, and ideas, and thus improve their own and other librarians' knowledge. By promoting, researching, teaching and learning music and other entertainment content through library services, we enable our users to find answers and solutions for their inquiries and needs. Such an integrated approach where all participants contribute to the common progress and development leads to a successful business coordination, and, as a result, a high quality and comprehensive collections of audiovisual materials have been built in the Zagreb City Library network. This concept can be applied as a successful model of development for audiovisual departments and collections in other libraries. Originality/value. With the development and maintenance of audiovisual collections, active cooperation within and outside the Zagreb City Library network, we want not only to preserve permanently the valuable musical and other materials, but also to improve the methods of access to music and other content to the mutual satisfaction of both library users and librarians. This paper presents the basic principles for the development of the above mentioned collections in the Zagreb City Libraries. These principles could serve as a model to inspire the development of the audiovisual collections in other public libraries. [ABSTRACT FROM AUTHOR]