The study of nations and ethnicities has been subject to recent trends, particularly, those denying substance to ethnicity and nation, but focusing on the way ethnicity and nation are socially constructed and ‘reified’ (constructivism–reificationism). In this article, this idea is tested on the Yugoslav case, where cases of reification are said to have been ‘arbitrary’. Such a position suggests that members of the Yugoslav federation went on their own ways because of ‘reification’ in the form of the republics and provinces. Although it is found that the republics and one province did enhance the process of national constitution, and although ‘ethnic entrepreneurs’ were active in the 1980s—a fact that is in line with a constructivist–reificationist theoretical position—there is one distinctive case that directly challenges such a position: Vojvodina did not opt for independence but, because of its Serb majority, it swiftly became integrated into Serbia. Moreover, the current article presents additional information to suggest that, although constructionist–reificationist approaches are relevant, they do not suffice to explain ‘nation’.