Abstract : Biological warfare, or the intentional use of living organisms or their toxic products in a destructive manner, has always been a subject of considerable discussion. This paper reviews the history of the development and use of biological agents and their toxins, with specific reference to the U.S. biological warfare program. This effort began in 1941 and evolved into a military-driven research and acquisition program, shrouded in controversy and secrecy. With the Presidential decision in 1969 to halt offensive biological weapons production, and the agreement in 1972 at the international Biological Weapons Convention to never develop, produce, stockpile, or retain biological agents or toxins, the program was modified into a defensive program. However, the scientific breakthroughs in biotechnology during the 1970s and 1980s that permitted the genetic sequencing and synthesis of toxins, and the continuing effort by the Soviet Union and several other nations to develop and stockpile such weapons made the future of biological warfare unclear.