Participation in CERN


CERN uses various legal instruments for governing its relations with States and international organisations. States and international organisations wishing to participate in CERN can either engage in institutional participation, which includes representation in the governing bodies of CERN, or in non-institutional participation, which normally covers scientific or technical collaboration.

Institutional participation

The principal instruments for institutional participation are Membership and Associate Membership. Both are open to States only. Since the introduction of CERN’s geographical enlargement policy in 2010, Membership or Associate Membership are open to States irrespective of their geographical location, subject to the fulfilment of certain criteria. Accession to either status is subject to a decision by the CERN Council. The benefits and obligations of Membership and Associate Membership, and the criteria and procedures for accession, are laid down in the CERN Convention and in CERN Council Resolution CERN/2918/Rev.


Member States enjoy all privileges of participation in CERN: access to scientific and technical programmes, staff employment, career development and training programmes, and industrial return. Member States participate in the governance of the Organization through their representation in the Council, CERN’s supreme governing body, with full voting rights. CERN presently has 22 Member States, which contribute to the budget of the Organization in proportion to their Net National Income (NNI).

Associate Membership

This status can either take the form of regular Associate Membership (of indefinite duration) or of Associate Membership as the pre-stage to Membership, normally for a period of between two and five years. Associate Members pay a reduced contribution to the CERN budget and enjoy benefits which are reduced accordingly. They are represented at the CERN Council, except at Closed Sessions, and do not have voting rights. CERN currently has three Associate Members in the pre-stage to Membership, Cyprus, Serbia and Slovenia, as well as four Associate Members, India, Pakistan, Turkey and Ukraine.

Observer status

Observer status has in the past been granted to States and international organisations. CERN currently has three Observer States (Japan, Russia and USA) and three Observer organisations (the European Union, JINR and UNESCO). This status has usually been awarded to States that have made significant contributions to the CERN infrastructure, and to international organisations which maintain close links with CERN. Observers may attend Open Sessions of the Council, and do not have voting rights. Collaboration with the Observer States on a scientific and technical level is governed by International Cooperation Agreements. In the framework of the geographical enlargement of CERN, Observer status will now be phased out for States, but maintained as an instrument for institutional participation for international organisations.

Non-institutional participation

International Cooperation Agreements

International Cooperation Agreements (ICAs) are the main instruments for implementing formal, non-institutional participation of non-Member States and territories in CERN programmes, and for regulating cooperation with international organisations. While ICAs provide the general legal framework for such cooperation, they are implemented through detailed Protocols and Addenda covering specific projects and programmes.

Memoranda of Understanding

Participation in scientific collaborations carrying out major experiments at CERN, as well as in the Worldwide LHC Computing Grid, future accelerator studies and certain other projects, are governed by multilateral Memoranda of Understanding (MoUs), signed by the participating institutes and their funding agencies and by CERN as the Host Laboratory. MoUs specify the financial and in-kind resources that the participants contribute to the construction, maintenance and operation as well as the upgrade of an experiment or project.

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