Abstract Since the introduction of the co-decision procedure by way of the Maastricht Treaty, the procedure has been transformed considerably. One of the most striking innovations is the possibility to adopt a legislative act in first reading. This article aims to answer the questions whether the increasing use of this fast track procedure is in line with Treaty provisions and/or intra/inter-institutional rules, and what the effects are of these stipulations. The empirical findings presented in this study indicate that two reasons for taking the fast track gain dominance in the practical political process, ie the political priorities of the Council and European Parliament (EP) and whether these actors consider a legislative file as urgent. From a study of two directives, it becomes clear that this dominance of factors has consequences for the type of early agreement reached (first or early second), the quality of the adopted legislation and its implementation at the national level.