AEIP has two different tiers of membership: Associate Members and Observer Members. In addition, AEIP has two different tiers of affiliation: Correspondents and Partnerships.

The Associate Members and the Observer Members are paritarian organizations. They can participate in the Statutory Commissions; however only the Associate Members have the right to vote.

The Associate Members also make up the Managing Board.

The Correspondents do not have to be paritarian and can only participate in the Task Force groups which are open to any organization who is interested in the works and topics of AEIP.

Moreover, through its Protocol of Cooperation, AEIP has established partnerships with social protection organizations outside of Europe who are dealing with similar issues.