The increasing number of cultural heritage digitisation projects being carried out both abroad and in Croatian libraries are a testament to the importance of cultural heritage and the efforts of cultural information institutions staff to carry out the highest quality digitalization projects to preserve old originals. The paper focuses on the topic of content, organization and presentation of collections in libraries with the aim of finding the most common group of users and their perception of collections. The frequency of user visits to the web pages of libraries and their digitized material is analyzed as well as the problems faced by librarians in the process of digitizing material. The theoretical chapter discusses cultural heritage in general, its types, legal and financial aspects of the protection of material and the aims and purpose of its digitisation. Emphasis is placed on criteria for the selection of materials and technology in addition to maintenance and their financing as common problems. Guidelines for the digitisation of cultural heritage, standards for metadata descriptions of collections are analyzed, with examples of some of the national digitisation projects. The paper examines the digitized material of the library of the National and University Library in Zagreb, the Library of the Croatian Academy of Sciences and the Public Library of Marko Marulić in Split, in order to describe the history of the collections, their interfaces and the state of the collections themselves, giving examples of the types and quantities of works that libraries contain. The focus of the research is on how library staff organize and present collections on libraries' websites, solve legal problems of copyright and access, and the appearance of the interface of the collections themselves.