A key area of debate within the public and academic library sectors across the world is use of physical space. Changing ideas about what a library should be, coupled with the growth of digital collections, has raised fundamental questions about how library buildings are used and the role of space in library services. Alongside these drivers is the need for libraries to produce data on services to inform their future development and design. This article is a case study from Loughborough University in the UK to evaluate the use of a large open learning/social space in the library. The investigation employs an ethnographic approach to gather data, a method little used in the field. Findings are explored under the following themes: collaborative study, individual study, social space, intrusions and interruptions, use of technology, diversity, library staff/library materials and spatial organization. The role of ethnographic studies within the library context is considered alongside the broader theoretical considerations of the use of physical space.