The Conference of Parliamentary Committees for Union Affairs brings together the EU affairs committees of national Parliaments, as well as Members of the European Parliament.
COSAC plenary meetings take place twice a year. At these meetings, each Parliament is represented by six Members. Each plenary meeting is prepared for by holding a meeting of the EU Affairs Committee Chairpersons.
The European Parliament delegation to COSAC is co-chaired by one of the Vice-President responsible for Relations with national Parliaments and the Chair of the EP Committee on Constitutional Affairs (AFCO).
The national Parliaments of the EU candidate countries are invited to participate with three observers each. COSAC meetings usually take place in the capital of the country holding the Presidency of the Council of the European Union.
COSAC was established in May 1989 at a meeting in Madrid, where the Speakers of the Parliaments of the EU Member States agreed to strengthen the role of national Parliaments in relation to Community matters by bringing together their Committees on European Affairs. The first meeting of COSAC took place on 16-17 November 1989 in Paris. The L COSAC meeting will take place on 27-29 October 2013 in Vilnius.
COSAC was formally recognised in a Protocol on the Role of National Parliaments in the European Union of the Treaty of Amsterdam which entered into force on 1 May 1999.
According to Article 10 of Protocol (No 1) on the Role of National Parliaments in the European Union of the Treaty of Lisbon, COSAC "may submit any contribution it deems appropriate for the attention of the European Parliament, the Council and the Commission. The Conference shall in addition promote the exchange of information and best practice between national Parliaments and the European Parliament, including their special committees. It may also organise interparliamentary conferences on specific topics, in particular to debate matters of common foreign and security policy, including common security and defence policy. Contributions from the Conference shall not bind national Parliaments and shall not prejudge their positions."