In this master's thesis, we investigate the meaning and significance of professional networking to Swedish librarians in their everyday professional practices. In addition, we explore the relationship between librarians' networking needs and the needs or expectations presented by their institutional context (i.e. the workings of their specific library organization or, more broadly, the library sector and work life). The study consisted of 1) a pre-study through an online survey directed to librarians at seven public libraries and four research libraries in Sweden 2) qualitative interviews with 21 public and research librarians recruited through the pre-study survey and 3) an additional interview with the chair of the Swedish national library association (Svensk Biblioteksförening). Overall, participants in the study rated the importance of their professional networks highly. When asked the significance of professional networks to everyday professional practice, the responses given by the interviewed librarians favored explanations in terms of 1) knowledge provision and learning, 2) interlinkage of library organizations with the goal of raising the standards of library service and 3) as a means of providing both professional and organisational support. Many of the study's participants also reported an expectation that they should network, citing either a direct expectation from library management or general trends in contemporary Swedish work life. Librarians' professional networking needs were related by respondents to characteristics of their institutional context, where some librarians pointed to factors such as sparse staffing or budget constraints as creating a need for professional support networks. This is a two years master's thesis in Library and information science.