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. An anonymous survey of 37 questions was sent to all professors, researchers and doctoral students of the University of Navarra. 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, and other pages and academic platforms). This percentage increased with the older respondents, who were also senior members of staff with tenure and positions of authority at the university. The decision to make publications accessible in open access depends on academic reward and on professional recognition. The services offered by the repository were generally perceived positively, with differences according to the age and subject area of the respondents. The awareness of those differences might help the university library to provide faculty with training and products that suit to their needs and habits.