Abstract: This paper analyses the present state of affairs of companies’ cross-border mobility in the EU after the ECJ’s judgment in Cartesio. This judgment is subject to an in-depth critical examination in light of the preceding case-law of the Court on companies’ freedom of establishment. Departing from Cartesio the paper enters into the debate about the adoption of new harmonization measures designed to remove the existing barriers on companies’ cross border mobility in the internal market that result from the divergent and deep rooted Member States’ companies’ private international law rules. The paper critically assesses the non-EU legislatives initiatives regarding the adoption of the long awaited 14th company law directive on the cross-border transfer of registered office. It argues that such a harmonization measure should now be finally adopted allowing companies to transfer their registered office alone from one Member State to another. That legal instrument must, in any event, respect the boundaries of the ‘abuse of law’ put forward by the Court in Cadbury Schweppes in the context of the exercise of the community right of establishment by companies in the EU.