Biological warfare is a potential threat on the battlefield and in daily life. It is vital for neurologists and other health care practitioners to be familiar with biological and toxic agents that target the nervous system. most illnesses caused by biological warfare agents are not commonly considered neurologic disease, however. Many of these agents (such as anthrax) may present with headache, meningitis, or mental status changes in addition to fever and other symptoms and signs (Tables 2 and 3). Thus, a neurologist may be consulted acutely to aid in diagnosis. Because of the incubation time of many biological agents and their protean manifestations, it is likely that health care workers will be on the front lines in the event of a bioterrorist attack. We must be prepared.