The Conference of Committees on Union Affairs of the Parliaments of the European Union (COSAC - the abbreviation of its French name, Conférence des organes spécialisés en affaires communautaires) facilitates regular exchanges of views between the committees on Union affairs of the parliaments of the Member States. In accordance with the Lisbon Treaty, the conference is empowered to inform the European Parliament, the Council and the Commission of any contribution that it deems appropriate. This conference also promotes the exchange of information and best practices between national parliaments and the European Parliament.

The decision to found COSAC was taken at the Conference of Presidents of the European Union in Madrid in 1989. The first meeting of COSAC took place on 16 and 17 November 1989 in Paris. According to its rules of procedure, COSAC meets twice during each six-month presidency in the presiding Member State - once in the format of the chairperson meeting and once in the plenary session. The European Parliament participates in the work of COSAC and so, as observers, do the committees responsible for European affairs / integration of the applicant countries.

The meeting of the chairs of the parliamentary committees for Union affairs is the first meeting that takes place within the parliamentary dimension of the Croatian Presidency. The meeting will present the priorities of the Croatian Presidency and discuss issues that are of common interest to the European Union and the national parliaments in their new legislative periods. The meeting of the chairs of the European committees is a preparation for the plenary session of COSAC, which will take place from 24 to 26 May 2020. The meeting will be streamed live on the internet.