Introduced by the European Single Act (1986), the procedure requires the Council of the European Union to obtain the European Parliament’s assent before certain decisions can be made.

The assent procedure applies mainly to the accession of new Member States, association agreements and other fundamental agreements with third countries. It is also required with regard to citizenship, the specific tasks of the European Central Bank (ECB), amendments to the Statutes of the European System of Central Banks and the ECB, the Structural and Cohesion Funds and the uniform procedure for elections to the European Parliament.

Lastly, the European Parliament gives its assent for the application of sanctions imposed on a Member State for a serious and persistent breach of fundamental rights and for closer cooperation in fields subject to the codecision procedure.