In this article, the author studies different possibilities an antitrust protection authority has, to recognize within an investigation on that matter the acceptance or not of a black market and pirate products traded together with original goods. The study takes as an initial position the existence of black markets that allow us to identify the criteria to define a relevant market, specially, software market. After carrying out these preliminary studies the article discusses the outlined problem; that is, whether original and pirate goods are replaceable. This issue starts to be solved with the software piracy study and the relationship between antitrust law and intellectual property. Afterwards, arguments in favor and against pirate goods being included in an antitrust process are sketched. Finally, the author's conclusion is presented over the relationship of original goods'pirate goods, inside an antitrust process.