The standard of Extraterritorial Application based on The Korean antitrust law-focused on Cartel, Dominant undertaking’s abuse, Mergers. The Korean antitrust law can be applied extraterritorially to anticompetitive practices entered into outside but implemented or producing effects within the Korean market. The Antitrust law applies to extra-territorial activities that were intended, and actually do, cause anticompetitive effects in Korea. The Korean antitrust law section 3(Application to Overseas Act) stipulates that in cases where any act that performs even abroad affects the domestic market, this Act shall apply to such act. According to this law, the Korea Fair Trade Commission(the KFTC) should prove the effects of the agreement on the Korean market. The test has been expounded upon by the Supreme Court’s judgment in the Air Cargo Cartel Case(Supreme Court decision, rendered on December 24, 2014, Case No 2012Du6216). In that case the Supreme Court considered the meaning and effect of Article 2-2 (current Article 3, while the wordings of the provision remains the same) of the Korean antitrust law and determined that jurisdiction over conduct that took place outside Korea will be presumed where the evidence demonstrates that the participants to the collusive conduct agreed that the Korean market was a direct target of that act with a clear and exact reference, link or connection to Korea or the Korean market (the 'Air Cargo Presumption of Direct Inclusion'). The Supreme Court went on to state that where the Air Cargo Presumption of Direct Inclusion does not apply, an extraterritorial act that has an effect on the Korean market is limited to an act that has a direct, substantial, and reasonably foreseeable effect on the Korean market. For the dominant undertaking’s abuse cases, the Korean antitrust law can be applied based on the above section 3. Where the abusive practice took place between foreign dominant firms and domestic firms, it is not clear to decide whether this practice is the mere application of the Korean antitrust law or the extraterritorial application of that. In the merger cases, the threshold of notification can work as a quantitative standard of extraterritorial application. As a result, the standard of the extraterritorial Application seems to be quite clear, compared with cartel or dominance cases. Recently the extraterritorial application issues of the Korean antitrust law and consumer protection law tend to be increasing. However, the expansion of the domestic law based on effect tests of extraterritorial application principle needs to be balanced with the comity, the reality of international relations and the scope and the limits of extraterritorial application. That is why the KFTC and the courts should strike a balance in deciding the extraterritorial application.