In June of 2003, McDonald’s Corporation announced that it would prohibit its direct suppliers from using antibiotics that are important in human medicine as growth promotants in food animals after 2004. The company also created a purchasing preference for companies that work to minimize antibiotic use. This announcement, coupled with recent Food and Drug Administration guidance on the same issue, will put pressure on the U.S. livestock industry to consider alternatives to feed-grade antibiotics. Denmark recently banned the use of feed-grade antibiotics in pork production and has been joined in this action by countries in the European Union. We traveled to Denmark last summer to talk to Danish veterinarians, farmers, economists, and industry analysts about how the ban was implemented and how the Danish pork industry responded to the changes. What we learned about the economic impact of the ban, as well as the effects on total antibiotic consumption, provides evidence of the likely economic impacts of a similar ban for the U.S. pork industry.