The international community has advanced in reforming the international aid system. Such reform comes at a time when there is a renewed skepticism about aid effectiveness and when the crisis sheds new doubts about the sustainability of donors´ commitments. At the same time, the international reality has changed as a consequence of the growing heterogeneity of the developing world, the new geography of global poverty, the emergence of new powers from the developing world, the presence of new aid players and, finally, the enlargement of the sphere of international public goods. Such changes demand a deeper reform in the development cooperation system. Introduction -- Aid and development finance -- Aid effectiveness -- Aid effectiveness: donors’ response -- Changes in the international system: challenges for aid policy -- Concluding remarks.