CTBTO - Comprehensive Nuclear Test Ban Treaty Organization

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) prohibits, on a worldwide scale, any nuclear weapon test explosion or any other nuclear explosion underground, in the atmosphere, the oceans, or in outer space. The Treaty was negotiated during the Geneva Disarmament Conference, passed by the 51st UN General Assembly on 10 September 1996 and submitted for signature on 24 September 1996.


So far the Treaty has been signed by 183 states, and ratified by 164 (as of July  2015). It will enter into force only after it has been signed and ratified by the 44 states listed in its Annex 2. These 44 states had certain levels of nuclear technology at the time the Treaty was drafted. Germany ratified the Treaty on 20 August1998. To enter into force eight more ratifications are needed: Egypt, China, India, Israel, Iran, North Korea, Pakistan and the United States. Of these states only India, Pakistan and North Korea have not yet signed. They are also the only states to have conducted nuclear tests after the CTBT was opened for signing in 1996.


After its entry into force, the Comprehensive Nuclear Test Ban Treaty Organization (CTBTO) will monitor the State Parties' compliance with the Treaty. Germany and the European Union consider its entry into force a major goal towards nuclear disarmament and non-proliferation.


Until the entry-into-force of the CTBT the Preparatory Commission of the CTBTO is in charge, consisting of a plenary body and several working groups which are composed of all State Parties, and the Provisional Technical Secretariat (PTS) based in Vienna. German Ambassador Wolfgang Hoffmann was appointed its first Executive Secretary. In August 2005 Ambassador Hoffmann was succeeded in the office by Tibor Tóth, followed in 2013 by Lassina Zerbo.


The mandate of the Preparatory Commission is to establish an International Monitoring System, its principal component being a network of 321 monitoring facilities established by each state and operated in collaboration with the PTS. Germany's contribution to this control network are five monitoring stations. Detailed information about some of these monitoring facilities is available on the website of the Federal Institute for Geosciences and Natural Resources - BGR (see link below). Even now the monitoring system with about 85% of the planned monitoring facilities already up and running is capable of detecting smallest underground nuclear explosions.


Following the United States and Japan, Germany is the third largest donor country to the budget of the Preparatory Commission, contributing 8.1 % (2015 overall figure: 105 million Euro).


For more information visit the website of the Federal Foreign Office


Contact CTBTO:
Executive Secretary: Ambassador Lassina Zerbo

Address: Wagramer Strasse 5, 1220 Vienna, Austria
Postal address: CTBTO, P.O. Box 1200, A-1400 Vienna, Austria
tel. (+43-1) 26030-6200
fax (+43-1) 26030-5941

Meetings of the CTBTO PrepCom

Have a look at the updated list of meetings of the CTBTO Preparatory Commission:

Germany's global commitments

Brochure Germany in the United Nations

Federal Foreign Office


Ever since joining the United Nations in 1973, Germany has demonstrated a continuously growing commitment to the UN system. This booklet highlights the German contribution to the work of the world organization in all its aspects.