Under the treaties, an IGC is called into being by the European Council, and is composed of representatives of the member states, with the Commission, and to a lesser degree the Parliament also participating.
Podľa zmlúv ju zvoláva Európska rada a skladá sa zo zástupcov členských štátov, Komisie a v menšom rozsahu sa na nej zúčastňuje aj Parlament.