(en) This dissertation is a theoretical and empirical contribution to the analysis of inter-organizational relations (IOR) between inter-governmental organizations, in the field of conflict management. Using social network analysis in the case of the interactions among European regional organizations (OSCE, EU, CoE and NATO) managing conflicts in South-Ossetia and Kosovo, this research demonstrates that IGOs'transorganizational action is driven by two main dynamics : collaborative advantage and structural power. Finally, with a new Database on Inter-Organizational Relations in Conflict (DIORc) the dissertation provides a novel instrument for the systematic analysis of inter-organizational relations.