The 41st IChO will be held in Cambridge, England in 2009.
The 40th IChO will be held in Budapest, Hungary in 2008.
The 39th IChO will be held in Moscow, Russia in 2007.
The 38th IChO was held in Gyeongsan, South Korea, July 1-11 2006.
The 37th IChO was held in Taipei, Taiwan, July 16-25 2005.
The 36th IChO was held in Kiel, Germany, July 18-27 2004.
The 35th IChO was held in Athens, Greece, July 5-14 2003.
The 34th IChO was held in Groningen, The Netherlands, July 5-14 2002.
The 33rd IChO was held in Mumbai, India, July 6-15 2001.
The 32nd IChO was held in Copenhagen, Denmark, July 2-11 2000.
The 31st IChO was held in Bangkok, Thailand, July 4-11 1999.
The 30th IChO was held in Melbourne, Australia, July 5-14 1998.
The 29th IChO was held in Montreal, Canada July 13-22 1997.
The 28th IChO was held in Moscow, Russia, July 14-23 1996.
The 27th IChO was held in Beijing, China, July 13-20 1995.
The 26th IChO was held in Oslo, Norway, July 3-11 1994.
The 25th IChO was held in Perugia, Italy, July 11-22 1993,
The 24th IChO was held in Pittsburgh and Washington, USA, July 11-22 1992.
The 23rd IChO was held in ?ód?, Poland, July 7-15 1991.
The 22nd IChO was held in Paris, France, July 8-17 1990.
The 21st IChO was held in Halle, German Democratic Republic, July 2-10 1989.
The 20th IChO was held in Espoo, Finland, July 2-9 1988.
The 19th IChO was held in Veszprém, Hungary, July 6-15 1987.
The 18th IChO was held in Leiden, The Netherlands, July 6-15 1986.
The 17th IChO was held in Bratislava, Czechoslovakia, July 1-8 1985.
The 16th IChO was held in Frankfurt, West Germany, July 1-10 1984.
The 15th IChO was held in Timi?oara, Romania, July 2-11 1983.
The 14th IChO was held in Stockholm, Sweden, July 3-12, 1982.
The 13th IChO was held in Burgas, Bulgaria, July 13-23 1981.
The 12th IChO was held in Linz, Austria, July 13-23 1980.
The 11th IChO was held in Leningrad, Soviet Union, July 2-11, 1979.
The 10th IChO was held in Toru?, Poland, July 3-13 1978.
The 9th IChO was held in Bratislava, Czechoslovakia, July 4-14 1977.
The 8th IChO was held in Halle, German Democratic Republic, July 10-19 1976.
The 7th IChO was held in Veszprem, Hungary, July 1-10 1975.
The 6th IChO was held in Bucharest, Romania, July 1-10 1974.
The 5th IChO was held in Sofia, Bulgaria, July 1-10 1973.
The 4th IChO was held in Moscow, Soviet Union, July 1-10 1972.
The IChO was not held in 1971.
The 3rd IChO was held in Budapest, Hungary, July 1-5 1970.
The 2nd IChO was held in Katowice, Poland, June 16-20 1969.
The 1st IChO was held in Prague, Czechoslovakia June 18-21 1968.