In August 1965, a report entitled "World Uranium and Thorium Resources" was published by the European Nuclear Energy Agency, on the basis of an examination carried out by the ENEA Study Group on the Long-Term Role of Nuclear Energy in Western Europe. It was foreseen at the time of publication that the results of this examination would need to be updated at intervals, and inDecember 1967 a second report, "Uranium Resources, Revised Estimates" was published. In order to enlarge the geographical coverage of the study, and to receive the advice of experts from uranium-producing countries outside the OECD area, this revision was made jointly with the International Atomic Energy Agency, Vienna. During 1968 a joint ENEA/IAEA Working Party prepared a first report on "Uranium Production and Short Term Demand", in an attempt to relate information on uranium production supplied by the members of the Working Party, with a prediction of the probable demand over the next ten years. The report was published in January 1969. In September 1970 a report on "Uranium Resources, Production and Demand" was published jointly by ENEA and the IAEA. This reportcontained an updating of the uranium resources position since 1967 which was again carried out by the joint ENEA/IAEA Working Party on Uranium Resources. In addition, the Secretariat had prepared estimates of uranium and separative work requirements which were annexed to the report.The present report is essentially similar to the previous one, in that it contains updated information on uranium resources, production and demand. Part II on Uranium Resources and Production was prepared in the framework of the joint NEA*/IAEA Working Party on Uranium Resources, as was the case in the three foregoing reports* The estimates of requirements for natural and enriched uranium, contained in Part III of the Report, have been prepared by a "Working Party on Uranium Demand", with an international membership set up for this purpose in spring 1972 by the NEA Study Group on the Long-Term Role of Nuclear Energy. As a result of this approach the estimates for uranium and separative work demand are based on corporately agreed input data, and the scope of the demand calculations has been extended considerably through access to relevant computer programs in several participating countries.