[en] During the first phase of the International Uranium Resources Evaluation Project (IUREP), data relating to the uranium potential of 185 countries were compiled and reviewed. Using these data, the NEA/IAEA Steering Group on Uranium Resources identified areas of the world thought to be favourable for the location of additional uranium resources and estimated the magnitude of these ''Speculative Resources''. A high percentage of the Speculative Resources is expected to be located within the major producing areas but the study has highlighted several other areas which, although they do not have at present known economic uranium deposits, could make a major contribution to uranium reserves in the future. In many countries, it will be necessary to perform exploration work beyond that at present being undertaken if a significant portion of the Speculative Resources is to be found. To encourage this exploration, a further IUREP evaluation, called the ''Orientation Phase'', has been initiated. (author)