This paper deals with the concept of institutional repositories and the role of librarians in their construction and maintenance. It is divided into two parts; the theoretical part, which is based on the available literature, and the research part. The theoretical part of the paper lists the characteristics of open access, as well as the benefits of institutional repositories in the context of contemporary scientific communication. There are benefits for individuals, institution and society, but also the possible obstacles that administrators/librarians can observe and overcome. The relationship between libraries and institutional repositories is being discussed; the tasks and activities of librarians are defined in the context of institutional repository management. In the research part of this paper, there are results of the research which was attended by a total of 80 Croatian librarians from the higher education/academic libraries. The research sought to examine the level of awareness and involvement of librarians in the area of development and maintenance of institutional repositories, as well as in the promotion of open access. The results of this research show that respondents are quite familiar with the concept of institutional repository, but also with open access activities. However, due to certain contradictions and ambiguities, there is a need for initiatives that could greatly affect areas of education, selfarchiving and cooperation with scientists and teachers.