Since the establishment of the WTO, the operations of businesses have beome more and more internationalized. Give the prevelaince of this situation, how to maintain the competion order in domestic market amid the mergers among multinational corperations, international cartel, and multinationals' abuse of their donaminating status in the market has recently become not only an issue of extraterritorial application but also an important subject for the competition law. Recently there had increased cases where Korean businesses were subject to extraterritorial application of competition law imposed by foreign authorities and more international cartel and mergers between multinationals outside Korean territory, which has not only negatively affected the competition order of Koea's domestic market but also caused damages to more and more consumers. Considering this, the Fair Trade Commission in Korea has formulated the policy for Extraterritorial Application of Competition Law targeting foreign businesses, for which administrative legislation was adopted to provide the extraterritorial application baisis for foreign businesses. For the places related to the jurisdiction issue of extraterritorial application, new regulations were set up for the document delivery by foreign businesses. Meanwhile, to enhance the efficiency of law enforcement, new regulations were formulated for the negotiation with the competition law authorities of foreign countries. Additionally, agreements on the negotiation with the foreign authorities on competition law implementation were also signed. All these have again highlighted the issue of the extraterritorial application of competition law. The purpose of this study was to explore the issue of extraterritorial application and its future development direction based on the survey of the legal basis for Korean law's extraterritorial application to foreign businesses and other substantive cases.