The competition itself is composed of a theoretical and practical element. The theory exams cover a wide range of Biology: Cell Biology, Molecular Biology, Plant Anatomy and Physiology, Animal Anatomy and Physiology, Ethology, Genetics and Evolution, Ecology, and Biosystematics. The marks are scaled so that the theory and practical components each have a weighting of about fifty percent.
Each year, the IBO is organized by a different country:
1. Former Czechoslovakia, Olomouc in 1990
2. Former Soviet Union, Makhachkala in 1991
3. Former Czechoslovakia, Poprad in 1992
4. Netherlands, Utrecht in 1993
5. Bulgaria, Varna in 1994
6. Thailand, Bangkok in 1995
7. Ukraine, Artek in 1996
8. Turkmenistan, Ashgabat in 1997
9. Germany, Kiel in 1998
10. Sweden, Uppsala in 1999
11. Turkey, Antalya in 2000
12. Belgium, Brussels in 2001
13. Latvia, Riga in 2002
14. Belarus, Minsk in 2003
15. Australia, Brisbane in 2004
16. China, Beijing in 2005
17. Argentina, Río Cuarto in 2006
18. Canada, Saskatoon in 2007
19. India in 2008
20. South Korea in 2009
21. Kazakhstan in 2010
22. Taiwan in 2011
23. Cyprus in 2012
24. Finland in 2013
25. Iran in 2014