The paper analyses soft law as a mode of EU governance. European soft law can be qualified as a relatively ‘new’ mode, notably due to its dramatic proliferation and the increasing involvement of private actors. The concept of ‘soft law’ is viable on the premiss that normativity may be graduated (‘the continuum view’). Soft law deploys specific legal effects apart from outright legal bindingness, and not merely political or otherwise factual effects. The legal effects of European soft law flow from the Member States’ general duty to cooperate (Art. 4(2) TEU). The paper then traces the emergence of EU soft law and establishes a typology distinguishing between institutional soft law, member States’ European soft law, and private self- and co-regulation (including technical and financial standard-setting). Next, some factors explaining the emergence of soft law as a new mode of governance are sought, and some undeclared policy goals such as competence creep, and the alleviation of private actors’ lack of formal law-making capacity, are highlighted. The relation between European soft and hard law is analysed in terms of soft law’s ‘pre-law’, ‘law-plus’, and ‘para-law’ functions. Finally, European soft law is evaluated along the parameters of effectiveness and legitimacy; and its overall significance for the European integration process is assessed.