In June 1979 the first direct elections to the European Parliament took place. In Denmark the results constituted a strong deviation from the normal party system. The turnout dropped to nearly half of that at the general elections, and the two biggest parties lost half of their votes, while a new list, the People's Movement against the EC, collected 21% of the vote. This article analyses the electoral behaviour in the European election in order to find an explanation for the deviation. It points out a difference between two conceptions of the election: some saw the election as an expression of party preferences, others as an expression of the fundamental attitude to the EC, a kind of referendum for or against Danish membership of the EC. Half of the electorate are against the EC, but most of them normally vote for pro-European parties, particularly the Social Democrats and the Progress Party. These voters were the crucial group in the Euro-election. Most of them did not vote, but the majority of those who did gave priority to their EC attitude and voted for the People's Movement. A distinct Euro-party system appeared, different from the usual pattern. The social and ideological basis of this new system is investigated, in particular the electoral profile of the People's Movement.