Judicial branch of the European Union (EU) , established in 1958 to ensure the observance of international agreements negotiated by predecessor organizations of the EU. Headquartered in Luxembourg, it reviews the legality of the acts of EU executive bodies and rules on cases of civil law between member states or private parties.
It can invalidate the laws of EU members when they conflict with EU law. Its bench, which is appointed by member governments, consists of 25 judges and 8 advocates-general. Prior to 2004, the ECJ met as a full chamber for all cases, but it now may sit as a "grand chamber" of 11 judges. See also International Court of Justice .