The BWC was the first multilateral disarmament treaty to ban an entire category of weapons of mass destruction, establishing a global norm against biological weapons.
Key Facts
- Opened for signature
- 10 April 1972
- Entered into force
- 26 March 1975
- States party (as of May 2025)
- 189 states
- Signed but not ratified
- 4 states
- Duration
- Unlimited
- Article VI invocations
- 1 (Russia, 2022)
By the Numbers
Cause → Event → Consequence
Following decades of biological weapons development by major powers during and after World War II, international concern grew over the humanitarian dangers posed by such arms. Existing treaties did not adequately prohibit biological weapons, prompting multilateral negotiations under the United Nations to close this gap in international disarmament law.
On 10 April 1972, the Biological Weapons Convention was opened for signature, prohibiting the development, production, acquisition, transfer, stockpiling, and use of biological and toxin weapons. It entered into force on 26 March 1975 and became the first multilateral treaty to ban an entire category of weapons of mass destruction.
The BWC established a strong international norm against biological weapons, and no state today openly declares possession or pursuit of such arms. However, the convention's impact has been limited by the absence of a formal verification regime, and notable violations occurred in Soviet and Iraqi offensive biological weapons programs.
Political Outcome
Treaty adopted, banning development, production, stockpiling, and use of biological and toxin weapons; entered into force 26 March 1975 with 189 states party as of May 2025.
No multilateral treaty banned biological weapons as a category; states could legally develop and stockpile them.
International law prohibited an entire class of weapons of mass destruction, creating a binding global norm against biological arms.