This chapter looks at the crisis-induced legal, institutional, and economic developments within the Economic and Monetary Union. It consists of two parts. First, there will be a brief sketch of the crisis-related developments. These include the setting-up of financial mechanisms, the European Central Bank’s interventions to combat the crisis, the enhanced oversight of national fiscal and economic policy, and the increased supervision over the financial sector. Second, there will be a ‘first assessment’ of their constitutional and structural implications. Two sets of issues will be examined here: issues of legal principle; and the bearing of the enacted measures on European economic integration. Three key arguments will be made in this chapter. First, it will be argued that the measures enacted have led to legislative fragmentation and have exacerbated problems of transparency and complexity which already existed in this area. Second, it will be shown that the chosen form of action has consequences for institutional balance in the EU, democratic control, and judicial review. Third, it will be argued that the enactment of measures which are only applicable to Euro area Member States has served to deepen economic integration within the Euro area and to further differentiate it from economic integration in non-Euro area Member States. Further, certain areas of the single market have integrated more deeply in the Euro area. It will be concluded that the various reforms which have been implemented have strengthened the EU economic governance framework from a legal, institutional, and economic perspective.