This chapter provides a systematic overview of the selected agencies explored in the previous chapter in the context of principal-agent theory. It compares the causes and nature of delegation, the scope of delegation and exercise of powers by the agencies, agency position in the system and information asymmetry, control mechanism and motivational structures and provides implications for the principal-agent theory and its application. Despite the fact that all EU agencies are unique, it was possible to derive several common features that have implications for the principal-agent theory. Notably the complexity of multiple principals in the environment, the presence of information asymmetry and expertise, the need of flexible delegation and autonomy, the issue of accountability, or the need for adaptability to the fast changing environment.