According to the most recent estimates, the population of third-country nationals residing in European Union countries is around 18.5 million, corresponding to 3.8% of the total population. Hence the management of the integration of immigrants in the European Union is one of the most challenging responsibilities that most Member States are facing today. Both countries with longer histories of immigration and countries that are experiencing immigration flows for the first time are being confronted with the need to define sustainable integration policies. The European Commission, also aiming to achieve this goal, has been supporting the Member States in formulating integration policy by developing common approaches for the integration of immigrants and in promoting the exchange of best practices. Among the most relevant recent developments in this area are the Common Basic Principles on Integration, the general framework for the integration of third-country nationals in the European Union adopted through the Commission Communication A Common Agenda for Integration, the Annual Reports on Migration and Integration, and the two editions of the Handbook on Integration for policy-makers and practitioners. Additionally, in 2008, the Council of the European Union adopted the European Pact on Immigration and Asylum and the European Ministerial Conference on Integration approved the Vichy Declaration. These EU documents concur in recommending a coherent, whole-of-government approach to integration, and working in partnership with immigrant communities.