There is clear evidence of biological weapons research and development by certain cults and militias as well as countries such as apartheid South Africa and Iraq. Further documents recovered from Al-Qaeda bases in Kabul suggest that some terrorist groups are taking an increased interest in biological weapons and would be prepared to use them. This demonstration of intent is compounded by a revolution in the biological understanding of toxins. A working draft of the human genome is now available, and already many toxin genes have been sequenced. With this new genetic knowledge and a general increase in protein engineering technologies have come new techniques for making novel toxins. Overall, the capability of employing biological weapons is not dependent on a single parameter, but is the product of a number of variables. Developing effective toxin biological weapons would require a number of separate enhancements, including the ease of production, greater environmental stability, enhanced targeting, and increased lethality. The basic tenets of threat assessment can be encompassed in questions about the actual threat and its validity; how to protect against the real threat; how to integrate the threat of emerging biomedical technologies into existing defense planning; the implications for current concepts of offense, defense, coercion, and deterrence; and the relationship between military and civilian society with reference to the threat. A coherent, integrated operational plan for dealing with all biological toxin threats will require threat/risk assessments, sophisticated global surveillance, integrated (government-military-civilian) reaction/response policies, and prospective logistical plans to provide appropriate medicines and equipment.