The imperative of effective competition law enforcement, particularly with regard to the most serious anti- competitive infringements in the form of cartels, requires the use of adequate methods for their detection. Among the most important mechanisms within the so-called reactive detection methods are the protection and rewarding of whistleblowers, which naturally gives rise to scholarly interest in this issue. In line with this research trend, this article presents the main assumptions underlying the protection and rewarding of whistleblowers in antitrust cases, the arguments for and against this mechanism, and the Polish legal solutions in this area. The entry into force of the Act of 14 June 2024 on the Protection of Whistleblowers, which constitutes a significant, though hardly groundbreaking, step towards improving the Polish whistleblower framework in antitrust cases, provides a particular impetus for this final strand of analysis. The main objective of the research is to verify the hypothesis concerning the growing importance of whistleblower protection and rewards as a complementary mechanism for detecting infringements of competition law, despite the lack of consensus on many issues related to this mechanism.