INTRODUCTION. The aim of this study was to determine the awareness of open access among the academic staff of a research-oriented Spanish university, their use of the institutional repository and their satisfaction with its services. METHODS. An anonymous survey of 37 questions was sent to all professors, researchers and doctoral students of the University of Navarra. Between 5 and 25 March 2015, a total of 1989 messages were sent by email with a link to the survey. RESULTS. A total of 352 responses (17%) were received. The responses showed statistically significant differences in opinions concerning open access journals and services created on top of the repository. Although there was general agreement on the need for open access, half the respondents adopted open access practices (which included the use of the institutional repository, personal and departmental pages and academic platforms such as Academia.edu and ResearchGate). This percentage increased with the older respondents, who were also senior members of staff with tenure and positions of authority at the university. The opinion on open access journals depended on the area of research and was related to the type of academic communication and career advancement in each discipline. Specifically, the opinions of researchers were similar within social sciences and humanities, within medicine and life sciences, and within the physical sciences. The repository services most valued were correction of bibliographic data among older researchers and document scanning among social sciences and humanities researchers. The interoperability of the repository with other systems (especially the current research information system) was also considered important.