T The oecd identifies cartel practices as the most dangerous form of business competition in the world due to their secretive nature and the difficulty of proving them. as an effort to address this issue, leniency programs have been effectively implemented to combat cartels in various countries, including south korea. although indonesia faces significant challenges in uncovering cartel practices, a leniency program has not yet been adopted in its competition law. the problem addressed in this thesis concerns the regulation and implementation of the leniency program in indonesia and south korea. this study employs normative legal research with a comparative law approach. the research is descriptive in nature and relies on secondary data. data collection is conducted through library research, with conclusions drawn using a deductive method. the results of the study indicate that the leniency program has not been implemented in indonesia due to the absence of a legal basis in law number 5 of 1999, in contrast to south korea, where the program has been implemented and regulated under the mrfta. the absence of a leniency program in indonesia weakens the kppu’s ability to prove cartel cases and to create a deterrent effect, whereas its implementation in south korea strengthens law enforcement and facilitates the disclosure of cartel cases.