Abstract: The cartel is perceived as the most dangerous form of anti-competitive action and in some jurisdictions it has dealt with cartel cases as a matter of serious and criminal sanctions. Cartel is a main criminal offense in the competition law. The subjects of cartel obtain many benefits from cartel behavior, like price fixing agreements and the territorial division of markets. These behaviors harm to consumers. The nature of the secrecy of the cartel is the biggest obstacle for business competition authorities to prove the existence of a cartel which is also experienced by the Business Competition Supervisory Commission in Indonesia. For this reason a large number of jurisdictions have adopted leniency programs to reveal the existence of cartels. Leniency program arrangement first implemented by the United States and also managed to hit the number cartel violation with the number of reporters or applicant for leniency program. Leniency program arrangement in the United States alone found in Corporate Program Leniency. This study discusses the obstacles faced by the Business Competition Supervisory Commission in Indonesia in revealing cartel practices based on business competition law in Indonesia and the possibility of implementing program leniency in competition law.