This chapter highlights the usefulness of Comparative Agenda Project data to study the Europeanization of parliamentary attention. Initially, the literature in the field has focused on the institutional and organizational responses to the challenges raised by European integration for national parliaments (Maurer and Wessels, 2005; Raunio and Hix, 2000; Raunio, 2009, 2005; Saafeld, 2005; Goetz and Meyer-Sahling, 2008; Auel et al., 2015b, 2015a; Finke and Herbel, 2015). More recently, scholars have started to look at the attitudinal and behavioral dimension, i.e., at what national members of parliaments (MPs) actually do in EU affairs.We join this literature and examine how and to what extent Europe is politicized in national parliaments. To answer this question, we rely on a longitudinal and comparative analysis of the Europeanization of parliamentary questions (PQs).