Abstract. The article focuses on the historical background and current state of the UN system of humanitarian agencies responsible for emergency relief and humanitarian aid in response to natural disasters and conflicts. Major stages of the system’s development and reform are identified, including initiatives to improve coordination of aid between the UN agencies, national governments and international humanitarian organizations. The author highlights a number of challenges and risks to current international humanitarian aid system. They stem from transformation of the international relations, growing information pressures and the specifics of the UN agencies’ funding system.