The scope of this chapter covers three main problematical issues within the transnational policing of organised crime: concepts, structure and impact. The first part discusses the way in which the policing of organised crime is not a settled phenomenon and is complicated by factors that include transformations in organised crime, differing academic approaches and social construction bias. The second part outlines and critically analyses the transnational policing infrastructure before concluding that, despite numerous academic studies and recommendations, much of this policing is done through a largely autonomous informal ‘cop-to-cop’ trust-based system. The final part critically assesses the benchmarking and measurement of effectiveness and impact and argues that a narrow form of self-assessment now defines this policing field.