Although price-fixing agreements remain per se illegal in the United States, courts have undermined the per se rule against price fixing by making it harder for plaintiffs to prove that such an agreement exists. For example, most courts that have considered the issue have held that defendants' price-fixing conduct in a foreign market is not probative of price fixing in the United States. This Article examines the relationship between foreign and domestic price-fixing activity and shows how expanding a price-fixing cartel from foreign markets into the United States benefits the cartel by reducing the risk of arbitrage, stabilizing the cartel, and concealing the conspiracy from global antitrust authorities. The Article then takes the insights from the empirical and theoretical cartel literature and applies them to antitrust doctrine in order to demonstrate why defendants' overseas price-fixing arrangements are relevant to proving the existence of an agreement in litigation claiming that the same defendants fixed prices in the American market. Finally, the Article encourages courts to better understand how international price-fixing cartels operate. Copyright.