When applying for a library card you normally need to show a valid ID and register your contact information. Some people cannot meet these requirements, e.g. undocumented immigrants, and this thesis examines how pub- lic libraries in Sweden act towards this group. The purpose of the study has been to examine which arguments have been used in the discussion regarding undocumented immigrants’ right to become library patrons, and to examine how the public libraries interpret the Swedish Library Act, which states that public libraries should be accessible to everyone. To examine how Swedish public libraries presently handles this question, a survey was sent out to public libraries in all of Sweden’s municipalities, and in three of them interviews were conducted and the public debate analysed. The thesis’ theoretical framework consists of recent year’s discussion in citizenship theory that challenges the notion of citizenship and suggests that presence and acts of citizenship grant even non- citizens certain civic rights in the modern welfare state. The results of the study show that some public libraries in Sweden have discussed how to act towards un- documented immigrants and have adapted their policies to meet the needs of this user group. The argument ana- lysis shows that the discussion regarding the undocumented immigrants’ right to become library patrons consists of a practical as well as an ideological discussion. The libraries want to be able to identify their users, but it is not a question of principle. In the political discussion, however, the opinion is expressed that individuals without permission to be in the country should not be granted access to public institutions such as public libraries. For the libraries, presence is more important than citizenship, and the Swedish Library Act, if somewhat vague when it comes to the rights of undocumented immigrants, supports these policy changes. This is a two years master’s thesis in Library and Information Science.