The congress was opened by Croatian Deputy Prime Minister Jadranka Kosor and was also addressed by ILH President Helmut Moritz.
The main topics to be discussed at the meeting, which lasts until 26 October, are humanism and world peace.
The ILH is a non-for-profit organisation of eminent scientists, cultural and public workers, religious dignitaries and other individuals promoting peace, trust and democracy around the globe.
The organisation was founded in Dubrovnik in 1974 and has been based in Sarajevo since 1998, the Croatian Government's Public Relations Office said in a press release.