A vital part of the Institute's dynamism, depth and international character is due to its continuously expanding and diverse membership. Individuals and institutions are encouraged to join I.I.R. and enjoy the benefits of an international relations network consisting of scholars, researchers and specialists. Membership benefits include a free subscription to the Annual Yearbook, the Occasional Research Paper Series and the Working Papers Series.

The cost is 44 Euro for students, 73 Euro for individual membership and 147 Euro for Institutions.