Abstract: The purpose of this article is to review the main challenges to the principle of free movement of persons in theory and practice in an enlarged European Union. The right to move freely represents one of the fundamental freedoms of the internal market as well as an essential political element of the package of rights linked to the very status of EU citizenship. The scope ratione personae and the current state of the principle of free movement of persons is assessed by looking at the most recent case law of the Court of Justice and the recently adopted Directive on the rights of citizens of the Union and their family members to move and reside freely within the territory of the Member States. But what are the hidden and visible obstacles to free movement of persons in Europe? How can these barriers be overcome to make free movement and residence rights more inclusive? This article addresses these issues along with the following questions: Who are the beneficiaries of the free movement of persons in an enlarged Europe? What is the impact of the recent legal developments in the freedom of movement dimension, such as the European Court of Justice case law and the new Directive? And to what extent are pro-security policies such as the Schengen Information System II and an enhanced interoperability between European databases fully compatible with the freedom of movement paradigm?