Every four years CIE organizes in one of its member countries a CIE session.
Each quadrennial CIE Session has, apart from Board meetings, a General Assembly meeting and Technical Division meetings, also a World Conference organized by the hosting National Committee of the country where the Session is held.
The CIE Session 2011 took place in Sun City, South Africa, from 9 to 16 July 2011.
The CIE Session 2007 took place in Beijing, China, from 4 to 11 July 2007.
The CIE Session 2003 took place in San Diego, USA, from 25 June to 2 July 2003.