The accident at the Fukushima Daiichi nuclear power plant in March 2011 − as a consequence of the Great East Japan earthquake − triggered a broad reflection on the question of the response to nuclear emergencies. As part of this, the UN Secretary General asked the Emergency Relief Coordinator, and Chair of the Inter-Agency Standing Committee (IASC), to study ways to enhance the capacity of the organizations of the IASC. This study and its recommendations reflect a broad consensus amongst the members of the humanitarian and nuclear emergency response communities, embodied, respectively, by the Inter-Agency Standing Committee (IASC) Sub-Working Group on Preparedness and by the Inter-Agency Committee on Radiological and Nuclear Emergencies (IACRNE). The study also acknowledges that many of the global-level issues identified in the United Nations system-wide study on the implications of the accident at the Fukushima Daiichi nuclear power plant have already been addressed or are in the process of being addressed.