Biological terrorism may be defined as the intentional use of microorganisms or toxins derived from living organisms to cause death or disease in humans, other animals, or plants in civilian settings. Improving surveillance for biological terrorist attacks that target livestock and improving detection and reporting of livestock, pet, and wild animal morbidity and mortality are important components of preparedness for a covert biological terrorist attack. The United States has a system for detecting and reporting nonendemic or foreign animal diseases, but the system needs strengthening to increase the likelihood of detecting a covert bioterrorist attack on humans or other mammals. To prepare for, prevent, respond to, and recover from an animal health emergency, the paper suggests, among other actions: (1) monitoring disease patterns via effective surveillance and herd health programs; (2) teaching and practicing preventive medicine; (3) educating veterinary clinicians, the public, producers, policymakers, and industry leaders regarding the threat and agents of concern; (4) developing emergency plans that include communication and diagnostic strategies; and (5) developing better coordinated intelligence capabilities and systems. References, appendix