How does ideological congruency affect the speed of legislative decision-making in the European Union? Despite the crucial importance of actor preferences, the effect of partisan alignments and ideological composition of the European institutions has largely been neglected. However, we argue that the ideological congruence between legislative bodies has an important effect on the duration of policy-making. We test our theoretical expectations based on a large new dataset on decision-making speed in the European Union using event history analysis. The findings confirm our theoretical claim indicating that the ideological distance between the European institutions slows down policy-making which has important implications for the problem-solving capacity of political systems more generally.