At the multilateral level, discussions or negotiations on the development of investment rules have proceeded in various forums, most recently at the QECD and the WTO. However these discussions and negotiations still do not bear satisfactory fruits. This paper surveys the history of the efforts to make an multilateral investment rules and discusses about the factors to make it so difficult, particularly focusing on the recent experience at the OECD and the WTO. This paper points out four difficult issues involved in the multilateral rulemaking on investment: the conflict between the interests of the developed countries and the developing countries; civil society`s increasing attention to the globalization and the investment rules; lacking recent interest of the U.S. in the multilateral investment agreement; concerns on the undermining of the regulatory powers of governments. A multilateral investment regime is required to facilitate improved economic efficiency and world welfare in the era of globalization. However, progress seems likely to be slow. It is becoming increasingly apparent that multilateral rule making on investment, by its nature, is difficult to negotate, since they touch on the entire range of matters relating to international production. It is a global agenda ahead of us how to achieve a broad consensus on this complex issue.