Joining the Biological Weapons Convention


A State can become a State Party to the Biological Weapons Convention (BWC) through two means: ratification or accession. Ratification is for States that have already signed the Convention, known as signatories. Accession is for States that have not already signed the Convention. Since the Convention entered into force in 1975, it is no longer possible to sign it but only to accede to it. Succession is for newly independent States which consent to be bound by a treaty to which the predecessor State was a party.

The domestic process for ratification or accession depends on the constitutional arrangements of the State concerned, but often formal approval by the national parliament is required. Once the domestic requirements have been satisfied, an instrument of accession or ratification should be deposited with one or more of the three Depositary Governments of the Convention: the Russian Federation, the United Kingdom, and the United States of America. Details on how to do so are provided below in the “Information on the Depositories” section. When the instrument is received by one or more of the Depository Governments, the State concerned then becomes a State Party to the Convention.

Ratification, accession and succession

Each State undertakes the process of ratifying, acceding or succeeding to the Biological Weapons Convention (BWC) in accordance with its own national constitutional process. The process is described in Article XIV of the Convention.

A State can ratify the Convention if it signed the BWC before its entry into force on 26 March 1975. A list of States which have signed but not ratified the Convention is available here. In order to ratify, a State should deposit an instrument of ratification with one, two or all three Depositary States (the Russian Federation, United Kingdom and the United States of America).See the contact details provided below.

A State can accede to the BWC if it did not sign the Convention before it entered into force on 26 March 1975. A list of States which have not signed the Convention is available here. In order to accede, the State should deposit its instrument of accession with one, two or all three Depositary States (the Russian Federation, United Kingdom and the United States). See the contact details provided below.

For States depositing their instruments of ratification or accession after the entry into force of the Convention, the BWC shall enter into force on the date of deposit.

A State that has become newly independent since the BWC entered into force on 26 March 1975 may also be eligible to succeed to the Convention. A State is eligible to succeed if the Convention had applied to it whilst it was part of another State e.g. when the application of the BWC was expressly extended to cover its territory by virtue of being a colony of a State party to the Convention. This information can be found in the lists of treaties that applied to the State before gaining independence that are normally transmitted to the new government by the former ruling State.

A newly independent State will not normally automatically succeed to the BWC – an instrument of succession is usually required, and is advisable in order to demonstrate the State’s express intent to be bound to the Convention. Some States have made general declarations of succession which should be backed up by formal instruments of succession to clarify their intent to join the BWC.

Instruments Instruments of Ratification, Accession and Succession come in many different forms according to the practice and procedures of the individual State. In the following section, models of instruments of ratification, accession and succession are provided for information purposes.

Variances in the texts of these instruments are of no importance, providing that the instruments clearly provide all the relevant information the depository needs to know. Above all, the instrument must give clear and unambiguous expression to the intention of the State to be bound by the Biological Weapons Convention. The instrument should therefore include:

  • name of the State;
  • the full title of the treaty and date when, and place where, it was concluded (The Convention on the Prohibition of the Development, Production and Stockpiling of Bacteriological (Biological) and Toxin Weapons and on their Destruction, opened for signature in London, Moscow and Washington, DC on 10 April 1972);
  • name and title of the person signing the instrument; and,
  • state where and when the instrument was issued.

In addition, the instrument itself should be:

  • the original document (a photocopy or scanned version of the instrument will not suffice);
  • signed by current personnel with full powers to do so (e.g. President, Minister of Foreign Affairs); and,
  • preferably affixed with the official seal of the Government.

Any queries, or requests for further information or assistance, can be directed to the Treaty Departments of any of the Depositaries (see contact details in the “Information on the Depositaries” section below) or to:

Biological Weapons Convention Implementation Support Unit
United Nations Office for Disarmament Affairs
United Nations Office at Geneva
Palais des Nations
CH-1211 Geneva 10
Telephone: + 41 (0)22 917 2230

Please click on the links below in order to display models of instruments for ratification, accession or succession to the BWC. These are provided for information purposes.

Model Instrument of Ratification

Model Instrument of Accession

Model Instrument of Succession

Information on the Depositaries

The depositary does the administrative work relating to a treaty. The text of a treaty establishes which State(s) or international organization is the depositary. The administrative work includes:

  • keeping custody of the original text of the treaty and any full powers;
  • receiving any signatures and receiving and keeping custody of any instruments of ratification, acceptance, accession or succession, any reservations or declarations, and all other notifications and communications related to the treaty;
  • examining whether the signature, or any instrument, notification or communication relating to the treaty, is in the correct and proper form, and in case of doubt, bringing the matter to the attention of the State in question. The depositary notes the date of deposit as the date on which it was received. If the instrument is in a foreign language, the depositary does not generally acknowledge receipt until the instrument has been translated and checked. For this reason, it is advisable to provide a suitable translation of the instrument if it has been written in a language foreign to that of the depositary; and,
  • informing States parties, and States entitled to become parties, of acts, notifications and communications relating to the treaty including proposals for amendments and adoption of amendments and notices of withdrawal from the treaty.

In the case of the BWC, there are three States that act as depositaries, and States not yet party to the Convention may deposit their instruments and other communications and notifications with any one of them, or a combination of the three. The three depositaries are:

  • the Russian Federation
  • the United Kingdom of Great Britain and Northern Ireland, and
  • the United States of America.

These depositaries maintain their own lists of States party to the Convention according to the instruments deposited with them, and liaise with one another when necessary to update their own lists of States parties and/or when more than one depositary receives an instrument from the same State.

In the case of the BWC, the Convention takes effect for a new State party on the day an instrument is deposited . The exact date the instrument is received by the depositary government is therefore crucial, as it determines exactly when a State is bound by international law to exercise the rights and obligations that the treaty concerned provides.

Instruments of ratification, accession and succession should be sent to the following addresses or transmitted through established diplomatic channels : Russian Federation

Legal Department

Ministry of Foreign Affairs of Russia

32/34 Smolenskaya-Sennaya Square

Moscow 121 200

Russian Federation

Telephone: 00 7 499 241 77 18

Fax: 00 7 499 241 11 66


United Kingdom

Treaty Section

(Legal Directorate)

Room WH MZ 23

King Charles Street

Foreign and Commonwealth Office

London SW1A 2AH

United Kingdom

Telephone: 00 44 207 008 1109



(Note: Envelopes should be marked “For the attention of the BWC Depositary”)

United States of America

Office of the Assistant Legal Adviser for Treaty Affairs

United States Department of State

Suite 5420

2201 C Street, N.W.

Washington, D.C. 20520

United States of America

Telephone: 00 1 202 647 1345



(Note: states wishing to deposit in Washington are advised to forward their instruments of ratification/accession to the Treaty Office through their embassies in Washington. Embassy staff should then call the Depositary Officer at the Treaty Office on the phone number above to schedule an appointment for hand-delivery of the instrument if desired.)