Normally chaired by the CoR's President, the main purpose of the plenary sessions is to:
- vote on opinions, reports and resolutions
- adopt the CoR's political programme at the beginning of each term
- elect a President, First Vice-president and the remaining members of the Bureau
- set up policy commissions within the institution
- approve the CoR's draft estimates for expenditure and revenue
- revise and agree on the CoR's Rules of Procedure.
The relevant CoR commission will appoint one of its members – known as the rapporteur – to draft an opinion on the legislative proposal which is then voted on during one of the CoR plenaries. If the opinion receives a majority of votes in its favour (simple majority), it is adopted and handed over to the other EU institutions for further scrutiny.
The CoR may also proactively adopt a position on a particular issue through an own-initiative opinion.