This article traces the emergence of an international law of disaster relief from a patchwork of norms through to a holistic body of international law. It argues that, for many years, the international law of disaster relief existed in piecemeal fashion. Since there is no overarching treaty on the subject at the global level, a hodgepodge of instruments have been concluded, namely subject-specific and disaster-specific treaties at the global level, regional and sub-regional agreements, bilateral agreements as well as soft law. However, through the work of the International Law Commission and the International Federation of the Red Cross and Red Crescent, a holistic body of international law relating to disaster relief is in the process of emerging. This article argues that this holistic body is emerging primarily as a result of three techniques that, while unconventional, are used relatively frequently in the making of international law. The three techniques are: (i) extrapolation from a series of piecemeal instruments to form a generalized standard; (ii) the use of analogy and (iii) the conclusion of instruments that are soft in form but contain a mixture of hard law and soft law. The way in which the techniques have been used to develop a body of international law relating to disaster relief is analysed, their use in other fields of international law discussed and limitations on their use in the disaster law context identified.