SINCE SEPTEMBER 11, 2001, federal, state, and local government agencies’ emergency response planning has focused on possible terrorist attacks using chemical, biological, radiological, nuclear, or high-yield explosive (CBRNE) weapons. Shortly after the destruction of the World Trade Center and the attack on the Pentagon, letters containing anthrax spores were mailed to media outlets and government officials. Twenty-two people became ill and five died. Although these acts of bioterrorism were limited, millions of people were made anxious and the routine act of opening the mail became dangerous. The U.S. Postal Service was disrupted, a Senate office building was shut down, and widespread psychological, behavioral, and social impacts were felt in affected communities. Before September 11, 2001, government agencies and public health leaders in states from representative regions of the country had not incorporated mental health as a component of their overall response plan to bioterrorism.1 Anticipating the psychological and behavioral consequences of a bioterrorist attack is now an urgent task facing our government’s leaders and our nation’s healthcare system. Understanding and planning for the public’s psychological response to terrorism has far-reaching implications for the practical management of a bioterrorist event. Bioterrorism raises special issues such as administering vaccination programs, distributing prophylactic medication, evacuation, isolation, and quarantine, all of which demand skilled psychosocial management. Developing a risk communication and public education program that addresses these concerns is essential to sustain the public trust and ensure people will follow directions that help control the spread of disease. CBRNE terrorist acts may be motivated by any number of objectives: wielding power to achieve a political goal, exacting revenge, punishing nonbelievers, or enacting an apocalyptic vision. The victims who are killed, injured, or even directly affected are rarely the primary target.2 It is the fear and terror instilled in the public’s psyche, the loss of one’s sense of personal and community safety, and the disruption of critical social infrastructure that can cripple a nation’s economy and leadership. In the immediate aftermath of a terrorist attack, individuals and communities may respond in adaptive, effective ways based on information and directions from trusted leaders or they may make fear-based decisions, resulting in unhelpful behaviors or even panic. Understanding the psychological responses to a CBRNE attack enables leaders and medical experts to talk to the public, promoting resilient healthy behaviors and sustaining the social fabric of the community. Recognizing the influence that psychological distress has on physical symptoms, illness, and injury allows medical personnel to more effectively triage and treat patients. Managing psychological distress that will be ubiquitous, as distinct from psychiatric illness, is appropriate and restorative and decreases the likelihood of future mental health problems.