Abstract A bioterrorism attack can affect the health of many different populations, even those that were not intended as targets. Whether the aim of an attack is humans, animals or crops, the result can be manifested in many species, including equids. Equids comprise a multibillion-dollar industry in the United States, and any disease that affects this trade can have a devastating impact on the economy. In addition, equids could potentially serve as sentinels of an attack against humans, or as amplifying hosts for certain diseases. Knowledge of what diseases have the greatest potential as bioterrorist or agroterrorist agents, how they may present, and what preventive measures are needed to stop their spread is the first step in preparedness. Surveillance for disease outbreaks in equids should be ongoing, with immediate reporting of any unusual findings to the appropriate veterinary and public health authorities.