The aim of this study is to show how some persons with one of the Swedish national minority languages as mother tongue use a library with regard to their mother tongue and culture. The research questions are: How do Sami-speaking, Finnish-speaking and Meänkieli-speaking (Tornedalen Finnish-speaking) persons use a library with regard to their mother tongue and their culture? What aspects do they find important in this use? As a theoretical frame I have used Marianne Andersson and Dorte Skot-Hansen’s model of the functions of the local library and Will Kymlicka’s theory of the value of maintenance of minority cultures. The study is a qualitative user study. Deep interviews have been conducted with 9 persons with Finnish, Meänkieli or Sami as mother tongue.The results show that the main use of the library is as a cultural centre and the most frequently used service is borrowing of literature. Most Finnish-speaking persons use the library this way and find it satisfactory. The Sami-speaking persons who read in Sami use the library but the small supply of Sami literature at the libraries is partly a limiting factor. The literature available in Meänkieli is limited, but some use the library to get access to this literature. Exhibitions and cultural arrangements are not attended very frequently and the library’s social function is not very prominent. Some persons use the library in their studies or in their profession to get access to literature in Finnish or Sami. The use of the library as information centre is minimal.The access to literature, the possibility to speak their mother tongue with the library staff and the highlighting of the literature and culture at the library are factors that are important and contribute to language-maintenance and strengthening of the identity. The accessibility to the literature itself and the children’s possibilities to use the library are also important factors. The study is a two years master’s thesis in Library and Information Science.