The fraudulent contracting of work is an important issue in many European countries today. EU and national policymakers have turned their attention to violations of the basic protection provided by employment law and collective bargaining that are linked to the fraudulent use of certain employment or commercial contracts. This report looks at these practices across the EU and examines measures initiated by national authorities, including labour inspectorates and the social partners, to identify, prevent and combat such practices. While governments and public bodies focus largely on improving regulation – reducing loopholes in legislation and strengthening detection and inspection – the social partners endeavour to achieve compliance, particularly through organising information and awareness-raising initiatives. Based on 29 national reports, covering the EU28 and Norway, the research finds that the potential of collective bargaining to respond to the challenges of fraudulent use of contracting work is largely underexploited. It points to the contribution that EU actors could make, given the crucial role of cross-border cooperation in detecting and sanctioning fraudulent practices involving a transnational dimension.