The “Guidelines on Fighting Cartels in Public Procurements” consolidates an institutional experience acquired by the Brazilian competition authority in its fight against cartels for more than twenty years. The main objective of the Guidelines is to orientate and support those who participate in the elaboration and execution of bidding procedures, such as auctioneers, members of public procurement commissions, authorities responsible for the investigation and punishment of illicit acts, and civil society. The guidelines display ways of identifying the main signs of existence of cartels in public procurements, in order to improve the detection, prevention and punishment of such illicit. The Guidelines are divided in four sessions. The first one presents a brief introduction regarding cartels in public procurements and a framework of the fight against this conduct. The session also highlights Cade’s main tools to detect cartels, such as Leniency Agreements, report a complaint online tools, economic analysis, screening, and dawn raids.