The co-operation procedure allows the EU Parliament to influence a minor part of the lawmaking in the EU (Article 252 kTEC). This procedure derives from the Single European Act of 1987.
If the EU Parliament proposes amendments, the Council can only reject them by voting unanimously. Since the Treaty of Nice entered into force, this procedure only remains for EMU matters.
The future
The EU Constitution abolishs this procedure and use co-decision and consultation instead. The Co-decision procedure will be called the ordinary legislative procedure.