There is a dearth of studies on librarians’ information practices, in particular their information use. At the same time the professional field of librarianship is infused with an imperative dictating that the work of librarians should be evidence based. This paper presents an ethnographic study of academic librarians’ information use in professional practice. On the basis of the analysis, which is rooted in practice theory, it is concluded that in the academic library under investigation, information use is an ongoing practice shaped in and by the specific areas in which the work is carried out. Rather than primarily relying on evidence in terms of formal research results, the librarians in the study relate to and make use of a multitude of both formal and informal information sources.