The court rules on disputes over EU treaties and other EU legislation. Its decisions are binding on EU institutions and member states.
A member state may be taken to court for failing to meet its obligations under EU law. Big fines can be imposed for non-compliance with the court's rulings.
The court hears actions brought by individuals seeking damages from European institutions, or the annulment of EU legislation which directly concerns them. It also clarifies points of European law at the request of courts in member states.
It is made up of senior judges from each member state, who hold office for a renewable term of six years.