The CERN convention was signed in 1953 by the 12 founding states Belgium, Denmark, France, the Federal Republic of Germany, Greece, Italy, the Netherlands, Norway, Sweden, Switzerland, the United Kingdom and Yugoslavia, and entered into force on 29 September 1954. The Organization was subsequently joined by Austria (1959), Spain (1961-1969, re-joined 1983), Portugal (1985), Finland (1991), Poland (1991), Czechoslovak Republic (1992), Hungary (1992), Bulgaria (1999), Israel (2014), Romania (2016) and Serbia (2019). The Czech Republic and Slovak Republic re-joined CERN after their mutual independence in 1993. Yugoslavia left CERN in 1961.

What does membership mean?

Member States have special duties and privileges. They make a contribution to the capital and operating costs of CERN’s programmes, and are represented in the Council, responsible for all important decisions about the Organization and its activities.

Who are our Member States?

Today CERN has 23 Member States: Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Greece, Hungary, Israel, Italy, Netherlands, Norway, Poland, Portugal, Romania, Serbia, Slovak Republic, Spain, Sweden, Switzerland and United Kingdom.

Cyprus, Estonia and Slovenia are Associate Member States in the pre-stage to Membership. BrazilCroatia, India, Latvia, Lithuania, Pakistan, Türkiye and Ukraine are Associate Member States.

Who has Observer status?

Japan and the United States of America hold Observer status with respect to the LHC, while the United States of America also holds Observer status with respect to the HL-LHC. The international organisations European Union and UNESCO currently have Observer status at CERN. The Observer status of the Russian Federation is suspended in accordance with the CERN Council Resolution of 8 March 2022. The Observer status of JINR is suspended in accordance with the CERN Council Resolution of 25 March 2022.

Over 600 institutes and universities around the world use CERN’s facilities. Funding agencies from both Member and Non-Member States are responsible for the financing, construction and operation of the experiments on which they collaborate. CERN spends much of its budget on building machines such as the Large Hadron Collider and it only partially contributes to the cost of the experiments.

Can non-members join CERN?

Non-Member States with international co-operation agreements with CERN include Albania, Algeria, Argentina, Armenia, Australia, Azerbaijan, Bahrain, Bangladesh, Belarus, Bolivia, Bosnia & Herzegovina, Canada, Chile, China, Colombia, Costa Rica, Ecuador, Egypt, Georgia, Iceland, Iran, Japan, Jordan, Kazakhstan, Lebanon, Malta, Mexico, Mongolia, Montenegro, Morocco, Nepal, New Zealand, North Macedonia, Palestine, Paraguay, Peru, Philippines, Qatar, Republic of Korea, the Russian Federation, Saudi Arabia, South Africa, Sri Lanka, Thailand, Tunisia, United Arab Emirates, United States and Vietnam. The Observer status of the Russian Federation is suspended in accordance with the CERN Council Resolution of 8 March 2022.

CERN also has scientific contacts with Bahrain, Costa Rica, Cuba, Ghana, Honduras, Hong Kong, Indonesia, Ireland, Kuwait, Luxembourg, Oman, Madagascar, Malaysia, Mauritius, Mozambique, Rwanda, Singapore, Sudan, Taiwan, Tanzania, Uzbekistan and Zambia.

How else do Member States exchange information?

Thematic forums bring together experts from CERN and Member States to exchange information and develop coherent strategies. Associate Member States may also participate. Existing forums are:

There are also recognised networks with their own governance: