Multilateral cooperation seeks to make effective the participation of the Autonomous Communities in the definition of the general interest, support for unity of action and respect for self-government and diversity.

The Sectoral Conferences are multilateral cooperation bodies relating to a specific sector of public activity. They are composed of the head of the competent Ministerial Department and all the Councillors of the Autonomous Governments responsible for the same subject. Because of their composition, number and activity, they constitute the main pillar of inter-administrative cooperation.

These are bodies constituted to voluntarily agree on actions that improve the exercise of the competences that each Public Administration has, they can have consultative, decision-making or coordination functions aimed at reaching agreements on common matters, in order to attend to the real problems of citizens.

Law 40/2015, of 1 October, on the Legal Regime of the Public Sector, establishes its legal regime in articles 147 et seq. Each Conference has an internal Rules of Procedure approved by its members. The Sectoral Conferences must be registered in the State Electronic Register of Cooperation Bodies and Instruments (REOICO) in order for their constitution to be valid. The seventh additional provision of this Law also provides for the registration that those cooperation bodies that have not met within five years of its creation or within five years of the entry into force of the Law will be extinguished.

In general, they have a working and supporting body, the Sectoral Commissions, which are responsible for preparing their meetings and monitoring the agreements adopted, usually set up working groups to carry out the technical tasks entrusted to them. There are currently 42 Sectoral Conferences, with a very heterogeneous level of activity.