Technical Abstract: Arthropod-borne diseases are an important part of the group of foreign animal diseases that command attention from federal, state, and local animal health authorities in the United States because of the potential for adverse local and regional animal health impacts, but also because of possible losses of export markets. Diseases of concern are listed by the United States Animal Health Association and also by the Office International des Epizooties (OIE). Global change is causing the emergence of newly recognized diseases and altering enzootic and epizootic circumstances for known disease problems. Selected examples of arthropod-borne diseases of importance are discussed in terms of their potential for introduction, spread, and impact on livestock and human health in the United States.