Comprehensive Nuclear-Test-Ban Treaty (CTBT)

History of the Treaty

The Conference on Disarmament (CD) began its substantive negotiations on a comprehensive nuclear-test-ban treaty in January 1994 within the framework of an Ad Hoc Committee established for that purpose. Although the CD had long been involved with the issue of a test-ban, only in 1982 did it establish a subsidiary body on the item. Disagreement over a mandate for that body blocked tangible progress for years.

Status of the Treaty

In accordance with Article XIV of the Treaty, it will enter into force after all 44 States listed in Annex 2 to the Treaty have ratified it.


The following Annex-2 States have ratified the treaty:

AlgeriaArgentinaAustraliaAustriaBangladeshBelgium
BrazilBulgariaCanadaChileColombiaDemocratic Republic of the Congo
FinlandFranceGermanyHungaryIndonesiaItaly
JapanMexicoNetherlands
(Kingdom of)		NorwayPeruPoland
Republic of KoreaRomaniaSlovakiaSouth AfricaSpainSweden
SwitzerlandTürkiyeUkraineUnited Kingdom of Great Britain and Northern IrelandViet Nam


The following Annex-2 States have not yet ratified the treaty:

ChinaDemocratic People’s Republic of KoreaEgyptIndiaIran
(Islamic Republic of)		Israel
PakistanRussian FederationUnited States of America

For more information on the ratification status of this treaty, visit the CTBTO website.

After more than two years of intensive negotiations, the Chairman of the Ad Hoc Committee, Ambassador Jaap Ramaker of the Netherlands, presented a final draft treaty to the CD in June 1996. An overwhelming majority of Member States of the CD expressed their readiness to support the draft treaty. India, for its part, stated that it could not go along with a consensus on the draft text and its transmittal to the United Nations General Assembly. The main reasons for such a decision, as India pointed out, were related to its strong misgivings about the provision for the entry-into-force of the treaty, which it considered unprecedented in multilateral practice and running contrary to customary international law, and the failure of the treaty to include a commitment by the nuclear-weapon States to eliminate nuclear weapons within a time-bound framework.

As a result, Australia, on 22 August 1996, requested that the General Assembly resume the consideration of agenda item 65, entitled “Comprehensive Nuclear Test-Ban Treaty” as provided for in resolution 50/65 of 12 December 1995. For that purpose, it also submitted the draft CTBT, identical to that negotiated in the CD, for adoption by the General Assembly.  On 10 September, the General Assembly by resolution (A/RES/50/245) adopted the Comprehensive Nuclear Test-Ban Treaty and requested the Secretary-General of the United Nations, in his capacity as Depositary of the Treaty, to open it for signature at the earliest possible date. The Treaty was opened for signature in September 1996.

On 29 May 2018, the Secretary-General launched “Securing our Common Future: An Agenda for Disarmament.” The Agenda highlights the norm against testing nuclear weapons of a measure that serves both disarmament and non-proliferation objectives. In that context, the Secretary-General appealed to all remaining States whose ratifications are required for the Comprehensive Nuclear-Test-Ban Treaty (CTBT) to enter into force to commit to sign the Treaty at an early date if they have not already done so, and to accelerate the completion of their ratification processes.

Latest Developments

Article XIV of the CTBT states that if the Treaty has not entered into force three years after the date of the anniversary of its opening for signature, a conference may be held upon the request of a majority of ratifying States. Such a conference is held to examine to what extent the requirements for entry into force have been met, and to decide on measures to accelerate the ratification process. Previous Conferences on Facilitating the Entry into Force of the Treaty were held in 1999, 2003 and 2007 in Vienna, and 2001, 2005 , 2009 , 2011, 2013, 2015, 2017, 2019, 2021, and 2023 in New York.

In years between conferences held pursuant to Article XIV of the Treaty, Foreign Ministers of CTBT Member States particular dedicated to the entry into force of the CTBT usually meet in the margins of the General Debate of the General Assembly of the United Nations in New York for CTBT Ministerial Meetings.

About the Preparatory Commission for the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO)


The Preparatory Commission for the Comprehensive Nuclear Test-Ban Treaty Organization (CTBTO)
is an international organization established by the States Signatories to the Treaty on 19 November 1996 and has its headquarters in Vienna, Austria. The objective of the organization is to achieve the object and purpose of the Treaty, to ensure the implementation of its provisions, including those for international verification of compliance with the Treaty, and to provide a forum for consultation and cooperation among Member States. To this end, the Commission prepares for the entry-into-force of the Treaty and carries out the necessary preparations for the effective implementation of the Treaty, including the establishment of a global verification regime. The Preparatory Commission consists of a plenary body composed of all States signatories to the Treaty and a Provisional Technical Secretariat.

The relationship agreement between the United Nations and the CTBTO was adopted in 2000 by the General Assembly as A/RES/54/280.

Documents and Resources

General Assembly Resolutions

Related Pages