The Seimas Committee on European Affairs has been actively engaged in meetings of COSAC that deal with the most important EU legislative matters and serve the purpose of exchanging views on strategic EU issues and the role of national Parliaments in the EU decision-making process and of sharing best practise.

The Committee on European Affairs is keen on cooperation among European Affairs Committees of the Parliaments of the Baltic States and Poland. Consultations among European Affairs Committees of the Parliaments of the Baltic States and Poland organised on a rotating basis prior to COSAC meetings have become traditional since their first meeting in 2005.

The exchange of best practices in COSAC has drawn attention to the role of the Seimas in exercising parliamentary scrutiny; LINESIS, a special information system of the Lithuanian membership of the EU, and other e-data parliamentary systems used jointly by the Seimas and other public authorities of the Republic of Lithuania have been recognised as model information systems.