At the celebrations of the 40th anniversary of the signature of the Treaty of Rome 1957 on 26 March 1997, Romano Prodi, President of the Italian Council, said that, with the Maastricht Treaty “we are perfecting our common economic constitution”, and that this Treaty should not be seen simply as an “instrument for the introduction of the single currency, but also as the awakening of the European peoples to the necessity of setting limits on the action of governments”. This notion of constitution or of economic constitution has received much attention from European legal scholars within the ongoing debate on constitutionalism and constitutionalisation within the Community legal order. However, constitutionalisation presents us with semantic difficulties, as legal doctrine has to adapt itself to the specificity of Community law. The discussion is further complicated by the divergence of views on the subject of whether the Treaties are a constitution for Europe and, indeed, whether Europe needs a constitution. Before we consider what constitutionalisation signifies, the notion of a constitution and an economic constitution in Community law merit consideration.