[en] This study addresses four arenas to assist national nuclear foreign policies under international nuclear nonproliferation regimes. Firstly, this study analyzes the trends of the international nuclear non-proliferation regime, which includes the Treaty on the Non-proliferation of Nuclear Weapons (NPT), the international nuclear export control regime, and fissile material cut-off treaty. Secondly, this study analyzes the trends of international nuclear organizations and fora, which include the International Atomic Energy Agency (IAEA) as a central body of international nuclear diplomacy and technical cooperation and International Framework for Nuclear Energy Cooperation (IFNEC) as a forum for international nuclear cooperation. Thirdly, this study analyzes the nuclear foreign policy of the U. S. Administration and reviews bilateral nuclear cooperation agreement between the ROK and the other countries including the U. S. Lastly, this study analyzes the nuclear issues of North Korea and Iran and multilateral nuclear approaches as assurances of nuclear fuel supply