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.