As part of the original Federal law known as the “Lacey Act” passed in 1900, injurious wildlife has been amended several times, but the purpose has always been to protect the United States from the introduction of invasive and otherwise harmful wildlife. Congress first gave the authority for overseeing injurious wildlife to the U.S. Department of Agriculture and later to the Department of the Interior. Injurious listing prohibits the importation of wild vertebrates, crustaceans, and mollusks that can cause harm to wildlife resources, humans, and other U.S. interests. However, most people know about a different provision of the “Lacey Act,” which is about trafficking of wildlife and plants. This presentation will explain what the “Lacey Act” is and the difference between the injurious and trafficking provisions. It will emphasize how the Service focuses on adding high-risk species to the Federal injurious list before they become established and how effective that has been in preventing the establishment of those injurious animals.