Co-chaired by a member of the House of Commons and a member of Dáil Eireann, elected from amongst the membership. It meets in plenary twice a year, and normally debates matters of political and general concern, considers reports from its committees and responses from the UK/Irish/devolved governments to questions raised. Committee reports, if approved by plenary, are forwarded to the relevant UK/Irish/devolved (if appropriate) government departments for a response.

The day-to-day work is carried out through four committees (Sovereign Matters (restricted to UK Parliament and Oireachtas members only); European Affairs; Economic Affairs; and Environmental and Social Affairs).