Purpose: The purpose of this paper is to analyze the role of public libraries as institutions underpinning a democratic public sphere as reasons legitimizing libraries compared to reasons that are more traditional and the actual use of libraries as public sphere arenas. Design/methodology/approach: A survey of representative samples of the adult population in six countries – Denmark, Sweden, Norway, Germany, Hungary and Switzerland – was undertaken. Findings: Legitimations related to the libraries role as a meeting place and arena for public debate are ranked as the 3 least important out of 12 possible legitimations for upholding a public library service. Libraries are, however, used extensively by the users to access citizenship information and to participate in public sphere relevant meetings. Originality/value: Few studies have empirically analyzed the role of libraries in upholding a democratic and sustainable public sphere. This study contributes in filling that gap.