In its legislative work, the Council is supported by committees and working parties which prepare its work and decisions. The Committee of Permanent Representatives of the Governments of the Member States to the European Union (Coreper) is the Council's main preparatory body. Coreper is composed of the permanent representatives from each Member State, who, in effect, are their country's ambassadors to the EU. It is chaired by the country holding the Presidency of the Council and is responsible for preparing all the work of the Council of the EU, apart from some agricultural matters.

To this end, it is supported by more than 150 highly specialised working parties and committees,  known as the 'Council preparatory bodies'. The preparatory bodies are either set up by the Treaties (or intergovernmental decisions or by Council acts), such as the Committee on Internal Security, or set up by Coreper.

In the first case, the preparatory bodies are mostly permanent, and contribute to preparing the work of the Council by providing analyses, reports and highly specialised opinions. The groups and committees set up directly by Coreper, on the other hand, examine proposals for legislation, undertake research and carry out all the work on the basis of which the Council's decisions are taken. They therefore deal with very specific issues ranging from research and nuclear energy to fruit and vegetables depending on the subject covered by the configuration of the Council in question. While some of them are set up on a temporary basis to deal with a particular dossier, about a hundred bodies cover a given sector and meet regularly.

Moreover, the General Secretariat of the Council regularly reviews the list of Council preparatory bodies.