[en] In Korea, twenty units of nuclear power plant are operating at present and especially Kori Unit 1 and Wolsung Unit 1 beyond twenty years. Usually it takes several years for operators to prepare the long-term decommissioning strategic plans of their own facilities before starting decommissioning, and also for regulator to revise the Atomic Energy Act and its regulations, which are the basis of operators' activities. In the light of this situation, it is time that we are going to check and, if necessary, to enhance the domestic regulatory institutional system for decommissioning of nuclear facilities. Of course, a lot of studies of the safety and costs for decommissioning have been carried out in domestic, but the study on the regulatory institutional aspects is less enough than them. At the Spring Proceedings of the Korean Nuclear Society in this year, the status of regulatory system for decommissioning of the EU countries, such as France, Germany and the United Kingdom, was presented. In this paper, the results of survey and analysis of the regulatory system for decommissioning of the United States of America (USA) and Japan is described. This will be also useful in developing of the direction of enhancement in our own system