The European citizens' initiative (ECI) is a new device of participatory democracy, which has its own characteristics, unknown to date at any level of national or trans-national government. It is designed to allow the citizens to take an active role within the law-making process of the EU. The specific features of this process affect the legal nature as well as the functioning of the new participatory device. Both will depend strongly on the European law, which shall determine the procedures and conditions required for the ECI.