The 46th IChO was held in HanoiVietnam, July 20–29, 2014.

Russia The 45th IChO was held in MoscowRussia, July 15–24, 2013.

United States The 44th IChO was held in Washington, D.C.United States, July 21–30, 2012.

Turkey The 43rd IChO was held in AnkaraTurkey, July 9–18, 2011.

Japan The 42nd IChO was held in TokyoJapan, July 19–28, 2010.

United Kingdom The 41st IChO was held in CambridgeEnglandUnited Kingdom July 18–27, 2009.

Hungary The 40th IChO was held in BudapestHungary, July 12–21, 2008.

Russia The 39th IChO was held in MoscowRussia, July 15–24, 2007.

South Korea The 38th IChO was held in GyeongsanSouth Korea, July 1–11, 2006.

Taiwan The 37th IChO was held in TaipeiTaiwan, July 16–25, 2005.

Germany The 36th IChO was held in KielGermany, July 18–27, 2004.

Greece The 35th IChO was held in AthensGreece, July 5–14, 2003.

Netherlands The 34th IChO was held in GroningenNetherlands, July 5–14, 2002.

India The 33rd IChO was held in MumbaiIndia, July 6–15, 2001.

Denmark The 32nd IChO was held in CopenhagenDenmark, July 2–11, 2000.

Thailand The 31st IChO was held in BangkokThailand, July 4–11, 1999.

Australia The 30th IChO was held in MelbourneAustralia, July 5–14, 1998.

Canada The 29th IChO was held in MontrealCanada July 13–22, 1997.

Russia The 28th IChO was held in MoscowRussia, July 14–23, 1996.

China The 27th IChO was held in BeijingChina, July 13–20, 1995.

Norway The 26th IChO was held in OsloNorway, July 3–11, 1994.

Italy The 25th IChO was held in PerugiaItaly, July 11–22, 1993.

United States The 24th IChO was held in Pittsburgh and Washington, D.C.United States, July 11–22, 1992.

Poland The 23rd IChO was held in LodzPoland, July 7–15, 1991.

France The 22nd IChO was held in ParisFrance, July 8–17, 1990.

East Germany The 21st IChO was held in HalleEast Germany, July 2–10, 1989.

Finland The 20th IChO was held in EspooFinland, July 2–9, 1988.

Hungary The 19th IChO was held in VeszpremHungary, July 6–15, 1987.

Netherlands The 18th IChO was held in LeidenNetherlands, July 6–15, 1986.

Czechoslovakia The 17th IChO was held in BratislavaCzechoslovakia, July 1–8, 1985.

Germany The 16th IChO was held in FrankfurtWest Germany, July 1–10, 1984.

Romania The 15th IChO was held in TimisoaraRomania, July 2–11, 1983.

Sweden The 14th IChO was held in StockholmSweden, July 3–12, 1982.

Bulgaria The 13th IChO was held in BurgasBulgaria, July 13–23, 1981.

Austria The 12th IChO was held in LinzAustria, July 13–23, 1980.

Soviet Union The 11th IChO was held in LeningradSoviet Union, July 2–11, 1979.

Poland The 10th IChO was held in TorunPoland, July 3–13, 1978.

Czechoslovakia The 9th IChO was held in BratislavaCzechoslovakia, July 4–14, 1977.

East Germany The 8th IChO was held in HalleEast Germany, July 10–19, 1976.

Hungary The 7th IChO was held in VeszpremHungary, July 1–10, 1975.

Romania The 6th IChO was held in BucharestRomania, July 1–10, 1974.

Bulgaria The 5th IChO was held in SofiaBulgaria, July 1–10, 1973.

Soviet Union The 4th IChO was held in MoscowSoviet Union, July 1–10, 1972.

          The IChO was not held in 1971.

Hungary The 3rd IChO was held in BudapestHungary, July 1–5, 1970.

Poland The 2nd IChO was held in KatowicePoland, June 16–20, 1969.

Czechoslovakia The 1st IChO was held in PragueCzechoslovakia June 18–21, 1968.