Does the trio presidency system enhance efficiency in EU legislative decision-making? Since 2007, fixed groups of three Member States have been required to set a joint 18-month agenda, with each Member State taking 6-month turns at the presidency. To date, however, there has been no empirical evidence that either confirms or refutes the notion that this system is efficient. In a study of the duration of Council decision-making on 1,927 legislative proposals for the 2000-12 period, we obtain empirical support for the hypothesis that a common agenda leads to a significant decrease in the amount of time needed to reach a first agreement on regulations, directives and decisions. In addition, we show that the requirement to pre-negotiate the agenda helps to moderate the effect of political conflict on the speed of decision-making, thereby offering support to the recent decision to proceed with the trio presidency system until at least 2030.