Purpose The purpose of this paper is to provide, through a set of indicators, an overview of the way in which Spanish institutional repositories are run and the services they offer their respective institutions and other users. The selected descriptors are based on aspects related to technology, procedures, content, marketing and the personnel responsible for managing repositories. Design/methodology/approach In order to establish the indicators, a thorough review of the literature was carried out to identify existing indicators that are used to assess repositories. These were divided into five categories (technology, procedures, content, marketing and personnel) with a total of 48 components. An online survey was conducted with the repositories managers of 66 Spanish research institutions in order to verify the degree of fulfilment of the selected indicators. Findings The survey received forty-six responses, which represented a response rate of 69 per cent. Of these, 44 came from universities and two from research centres. In total, 65 per cent of the repositories have the capacity to import data from and export data to other university systems, mainly Current Research Information System (32 per cent). Most repositories have mechanisms for the large-scale import and export of metadata and digital objects (83 per cent). The use of altmetrics in repositories is widespread (44 per cent). Authors and librarians deposit most frequently (37 and 32 per cent, respectively), in spite of the fact that 44 per cent do not have full-time staff working in the repository. In more than 80 per cent of the repositories, between 90 and 100 per cent of the deposits are full-text documents. With respect to the tools used to promote the repository within the institution, these are primarily face-to-face training sessions (82 per cent), followed by support materials such as manuals and help pages (65 per cent). The academic authorities encourage open access among researchers in 56 per cent of cases, a significant element in repository marketing. Originality/value This work proposes a model based on five dimensions and 48 indicators to assess institutional repositories. This approach has been applied to Spanish institutional repositories to provide up-to-date information about their management procedures and promotional methods and the services they offer authors and the university community. This overview of Spanish repositories has provided an insight into the way in which repositories have evolved in recent years and allowed potential improvements to be identified based on the most advanced repositories. This model can also be exported to assess institutional repositories in other countries.