Trends in food production are discussed with particular reference to the developing countries and their food needs. The yields now being obtained are compared with the known potential. The history of fertiliser use in developing countries is described and usage in these areas compared with developed regions. The contribution of fertilisers to increased yield is discussed, more particularly as illustrated by results of FAO trials and demonstrations on small farmer holdings and in the light of the general correlation that is evident between yield level, farming intensity and fertiliser usage. Regional and national differences in the pattern of feritliser usage and the main factors which affect fertiliser consumption in developing countries are described. Particular attention is paid to constraints which hinder the wider use of fertilisers and the measures which should be taken to overcome them and the part which can be played by government policies. A plea is made for greater international cooperation in this field, by exchange of experience in the provision and distribution of fertilisers and the effectiveness of produce and fertiliser pricing policies. Finally the various forecasts of the fertiliser needs of developing countries are discussed and it is concluded that that made by the Working Group of FAO/UNIDO/Worldbank, which puts world demand for 1988/89 at 171 million tonnes of which the developing countries will use 55 million, is the best informed and most probable.