The Organization
The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) was set up in 1996 with its headquarters in Vienna, Austria. It is an organization tasked with building up the verification regime of the Comprehensive Nuclear-Test-Ban Treaty (CTBT) in preparation for the Treaty's entry into force, as well as promoting the Treaty's universality.
Its provisional secretariat has over 300 multi-disciplinary professional and support staff from approximately 93 Member States.
The CTBTO is financed mainly through assessed contributions by Member States. Its budget for 2025 is US$ 139.31 million.
The Commission consists of two main organs:
- A plenary body composed of all States Signatories (Member States), which is also referred to as the Preparatory Commission. This is assisted by three groups: a working group on administrative and financial issues (Working Group A), another on verification-related issues (Working Group B) and an advisory group.
- The Provisional Technical Secretariat (PTS), which assists the plenary body in carrying out its activities. The PTS has three technical divisions: the International Monitoring System (IMS) Division, the International Data Centre (IDC) Division and the On-Site Inspection (OSI) Division. These are supported by a Legal and External Relations Division, a Division of Administration and Human Resources Services.
The Preparatory Commission
The Preparatory Commission for the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) was established on 19 November 1996 by a Resolution adopted by the Meeting of States Signatories at the United Nations in New York.
The Provisional Technical Secretariat
The main function of the PTS is to assist the Preparatory Commission in the establishment of a global verification regime to monitor compliance with the comprehensive ban on explosive nuclear testing.
CTBTO After Entry into Force
Several developments will take place once the Comprehensive Nuclear-Test-Ban Treaty (CTBT) enters into force, 180 days after the date of deposit of the instruments of ratification of all the 44 States listed in Annex 2.