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Date established

19 November 1996

The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO Preparatory Commission), established by the States Signatories to the Treaty on 19 November 1996, is mandated to carry out the necessary preparations for the entry into force and effective implementation of the Comprehensive Nuclear-Test-Ban Treaty (CTBT). This includes the establishment of a global verification regime to monitor compliance with the Treaty.

The Treaty was adopted by the UN General Assembly on 10 September 1996 and opened for signature on 24 September 1996. Article I prohibits all nuclear weapons test explosions or any other nuclear explosions. Each State Party further undertakes to refrain from causing, encouraging or in any way participating in the carrying out of any such test or explosion.

The Treaty will enter into force 180 days after it has been signed and ratified by the 44 states listed in Annex 2 to the Treaty. These countries possessed nuclear reactors or research reactors and participated in negotiations for the Treaty in 1996. Under article XIV, if the Treaty had not entered into force three years after its opening for signature, a Conference on Facilitating the Entry into Force was to be convened. Several such conferences have taken place, most recently in September 2009 in New York. The next one is scheduled to be held on 23 September 2011 in New York.

The Preparatory Commission for the CTBTO consists of two main organs:

  • A plenary body composed of all States Signatories
  • The Provisional Technical Secretariat (PTS).

The plenary body has three subsidiary organs:

  • Working Group A on budgetary and administrative matters
  • Working Group B on verification issues
  • An Advisory Group consisting of financial experts from States Signatories.

The verification regime is made up of a 337-facility International Monitoring System (IMS)- 321 monitoring stations supported by 16 radionuclide laboratories around the world that monitor the earth for signs of a nuclear explosion. Seismic, infrasound and hydro-acoustic stations monitor the underground, atmosphere and oceans respectively. Radionuclide stations detect radioactive debris emanating from an explosion. The IMS stations send data to the International Data Centre (IDC) in Vienna where it is processed, analysed and forwarded to Member States for their evaluation and judgement. As of May 2011, 267 of the facilities were completely installed and certified, and sending data continuously or upon request to the IDC. The verification regime also includes on-site inspections in the event of a nuclear explosion, a consultation and clarification process, as well as confidence-building measures.

The data from the CTBTO verification technologies can be used in a variety of civil areas, including scientific research, disaster preparedness and meteorological and climate forecasting, such as tsunami warnings. Since November 2006, the Commission has been providing real-time and continuous data to tsunami warning organisations in the Indo-Pacific region.

A state becomes a member of the Preparatory Commission for the CTBTO upon signing the CTBT. Member States oversee the work of the Preparatory Commission and fund its activities.

As of 20 June 2011, there were 182 States Signatories. Of these, 154 had deposited their instruments of ratification. Thirty-five of the 44 Annex 2 states (whose signature and ratification is required for the Treaty to enter into force) had ratified the Treaty including three nuclear weapon states, France, Russian Federation and the UK The most recent Annex2 state to ratify the Treaty was Colombia, which did so on 29 January 2008.

As of May 2011, nine Annex 2 States had not yet ratified the Treaty: China, DPRK, Egypt, India, Indonesia, Iran, Israel, Palcistan and the USA. DPRK, India and Pakistan are also yet to sign the Treaty.

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