In this article, we critically discuss the democratic legitimacy of deliberative experiments taking place in a transnational setting. We argue that while deliberative polls through scientific design may enhance equal participation and informed opinion making of selected citizens, their representative status as part of a broader constituency and as a generator of democratic legitimacy is less clear-cut. To illustrate our argument, we analyse the results and organisation of Europolis, a transnational deliberative experiment. This is an ideal case for analysing the linkage between scientific validity of deliberative experiments and democratic legitimacy because it introduces variation in terms of constituency and group plurality. By critically scrutinising this deliberative event, we provide a first take on specifying scope conditions for deliberation, with direct reference to the lessons from the experiment, reflection on methodological problems and, finally, an attempt to discern ways to move from deliberation to will formation in the EU setting.