Recent research on national parliamentary control of European Union affairs relies primarily on cross-sectional, contemporary data, whereas information on the nature and frequency of changes within countries and over time is currently lacking. This lack of data not only limits our substantive knowledge of the role of national parliaments in EU affairs but also constrains studies of the causes of parliamentary control. This research note offers a cross-national and longitudinal comparison of all member state parliaments from 1958 to today. Thus, it refines and updates recent measurements and provides a starting point for more conclusive analyses of cross-national and temporal variation.