Delegation of powers and functions to semi-detached bodies inside European Union represents an interesting and partially new case of organisational governance change. The EU’s institutional setting influences the evolution of this process and its characteristics. At the light of the main public management theories on delegation, this phenomenon is assessed, in order to define a “model” of European agency and to discuss the features characterizing the relationships between the principal (the European Commission) and the agents (the EU’s agencies) and in more general terms, the networked relationships between the EU’s agencies and their stakeholders. A brief presentation of the overall system of delegation inside EU is integrated by a discussion of the findings resulting from an analysis of two specific case studies: the ones of EMEA (European Medicines Agency) and EEA (European Environment Agency).