This chapter examines the consequences of integration in the European Union in relation to varying conceptions of nationality and citizenship, in the context of debates about the creation of a European citizenship. It goes on to explore possible exclusionary outcomes of the process of integration for certain kinds of residents within the Union and of those seeking residence, particularly third country nationals. In doing so I question the feasibility of creating such a thing as a ‘real’ citizenship of the Union. Roche (1997) uses the term ‘social exclusion’ as one aspect of a ‘constitutional exclusion’ and identifies both a broad and a narrow meaning. Narrowly it might refer to problems of poverty and unemployment, with ‘social inclusion’ linked to policies to try to ameliorate them. In the broader sense it can refer to all forms of discrimination and barriers to social inclusion including political, civil and cultural exclusions, and encompassing racism and ethnic discrimination. European citizenship was developed by the Maastricht Treaty in 1991/92, and endorsed by the Amsterdam Treaty (Maastricht 2) in 1996, and is a developing concept.