Institutional repositories are information systems that are institutionally defined and which make scholarly material widely accessible to the community. Repositories are a key service in supporting the mission and goals of their institution and can be seen as a digital embodiment of research activity. However, institutional repositories should be viewed as supplements and not as primary venues for scholarly publishing. To be successful, institutional repositories must be filled with scholarly work that can be searched and cited. This chapter describes the advent of institutional repositories, their role in scholarly communication and how they changed the profession of librarians. The main focus is on examining institutional repositories as instruments of monitoring research performance by discussing the metrics that repositories currently offer. Most commonly measured repository metrics are the number of items, item downloads, item uploads and citation-based metrics. These metrics are either platform-generated or result from interlinked databases to retrieve citations. Institutional repositories and bibliometrics as a method of research evaluation have gone through a redefinition of their role and tasks in recent decades. As there is no established standard of performance indicators, repository managers should be careful with interpretation of metrics.