It has become commonplace to assert that museums embody, perform and negotiate national identities. Many researches in museum history have stressed a close relationship between nation building and the origin and formation of the modern public museum. Museums, it is argued, contributes to the construction and repre-sentation of the ethnical and historical distinctiveness of the nation’s self’. This article explores the ambiguities of the concept when applied to the establishment of cultural history museums in Sweden and Norway during the latter half of the 19th century. It shows that the relation between nation building and early museum building in the Scandinavian context was more intricate than earlier has been assumed. Museum founders like Artur Hazelius, who opened the Scandinavian-Ethnographic Collection in 1873 (renamed Nordiska museet 1880), was deeply influenced by Scandinavianism, a strong cultural and political force during the 19th century. Union politics played an important role for museum politics, as did the transitions of the concepts of “ethnography” and “nation”. At the very end of the 19th century the original concept of “nation” meaning people and culture gradually was subordinated to the concept of “nation” as state and political territory. In early 20th century museum ideology cultural history museums were strongly connected with “nations” in the modern sense. Consequently, efforts to “nationalise” the folk-culture museum were made both in Norway and Sweden. A contributory force was, naturally, the dissolution of the Swedish-Norwegian union in 1905.