This article examines some of the ways in which the states have contributed to important developments in the antitrust laws, both historically and in the present. Although they are resource constrained, the states have made a significant impact on the overall direction of the antitrust laws, by bringing a consumer-centric analysis to anticompetitive conduct and legislation. While the states often work cooperatively with the federal enforcers, there are many examples throughout history, and recently, where states have acted independent of the federal agencies. The article concludes that concurrent jurisdiction of the antitrust laws is beneficial and produces the best outcomes for consumers.