The aim of the paper is to analyse party attitudes towards the European Union (EU) and the issue of citizenship as voiced by the party central office in the official programmatic platforms. For this purpose, Euromanifestos have been coded by applying the common framework of the IntUne project. Accordingly, the article attempts to assess the degree of convergence between the attitudes of both the party central office and the MPs towards the EU in Greece, Italy, Portugal and Spain. The article attempts as well to assess the validity of the main theoretical arguments available in the literature that explain these attitudes.