Few subjects are as controversial in international law today as the taking of foreign property. Many of the developing countries assembled within the framework of the semi-official Group of 77 (G. 77) claim that many of the principles and rules pertaining to the protection of foreign property traditionally adhered to by Western developed countries have lost their legal significance; in particular, as a result of legal developments induced by relevant UN resolutions. The question is, to what extent this claim is correct; to what extent the traditional rules have indeed been replaced by new ones, and what the contents of these new rules might be. The present study tries to answer this question, and sets out to review and analyze: first, the main doctrines of traditional customary law concerning the taking of foreign property (Part 2); secondly, the relevant UN resolutions relative to this subject (Part 3); and thirdly, state practice as it manifests itself in the form of one multilateral and 195 bilateral investment protection treaties concluded up to 1983, both between developed and developing countries and amongst developing countries inter se. (Part 4). On the basis of this review and analysis conclusions are drawn in Part 5.