Created in 1973, the European Commission’s Eurobarometer program now constitutes the main and sometimes exclusive source of studies on the opinions of Europeans on the integration process. Through their secondary analysis of Eurobarometer data as well as their direct collaboration in the program, academics have played a great part in giving it a virtual monopoly over the empirical analysis of European attitudes. Despite this closeness to academic circles, the Commission’s program has never ceased to be a political instrument; first used to measure the “meteorology of opinion” for the EU’s information policy, then as a forward studies tool for the agenda-setting and publicization of Community action. Retracing the double (intellectual and political) genesis of “European opinion polls”, this paper shows that their basic ambivalence is sociologically rooted, beyond the institutional, social and chronological coordinates of the Eurobarometer. The analysis follows the transformations of the world of EU opinion polls, which started developing in the 1950s ' around Community agents, academics and polling professionals and led to the invention of “European public opinion.” In the process, another history of the role (and of the enrolment) of academics in the construction of political Europe is told.