Countries in IChO

National teams participated in the IChO

Table 1: The number of countries and participants in the IChO

IChO	City	Year	Number of countries	Number of participants
1^st	Prague	1968	3	18
2^nd	Katowice	1969	4	20
3^rd	Budapest	1970	7	28
4^th	Moscow	1972	7	28
5^th	Sofia	1973	7	28
6^th	Bucurest	1974	9	36
7^th	Veszprem	1975	12	48
8^th	Halle	1976	12	46
9^th	Bratislava	1977	12	47
10^th	Torun	1978	12	48
11^th	Leningrad	1979	11	44
12^th	Linz	1980	13	52
13^th	Burgas	1981	14	55
14^th	Stockholm	1982	17	68
15^th	Timisoara	1983	18	72
16^th	Frankfurt	1984	20	80
17^th	Bratislava	1985	21	83
18^th	Leiden	1986	22	86
19^th	Veszprem	1987	26	103
20^th	Espoo	1988	26	104
21^st	Halle	1989	26	104
22^nd	Paris	1990	28	112
23^rd	Lodz	1991	30	118
24^th	Pittsburgh	1992	33	131
25^th	Perugia	1993	37	148
26^th	Oslo	1994	41	156
27^th	Beijing	1995	42	163
28^th	Moscow	1996	45	175
29^th	Montreal	1997	47	184
30^th	Melbourne	1998	47	186
31^st	Bangkok	1999	51	196
32^nd	Copenhagen	2000	54	208
33^rd	Mumbai	2001	54	213
34^th	Groningen	2002	57	225
35^th	Athen	2003	59	232
36^th	Kiel	2004	61	233
37^th	Taipei	2005	60	225
38^th	Gyeongsan	2006	67	254
39^th	Moscow	2007	67	256
40^th	Budapest	2008	66	257
41^st	Cambridge	2009	64	250
42^nd	Tokyo	2010	68	267
43^rd	Ankara	2011	70	273
44^th	Washington	2012	72	283
45^th	Moscow	2013	73	291
46^th	Hanoi	2014	75	291
47^th	Baku	2015	74	290
48^th	Tbilisi	2016	73	264
49^th	Nakhon Pathom	2017	76	296
50^th	Bratislava, Prague	2018	76	300
51^th	Paris	2019	86	309
52^th	Istanbul	2020	60	231
53^th	Osaka	2021	80	291
54^th	Tianjin	2022	84	326
55^th	Zurich	2023	86	348

Graph 1:

Graph 2:

Compiled and edited by A. Sirota (IChO Intern. Information Centre)

Contact us

Dr. Anton Sirota|Director of the IChO IIC
NIVaM – National Institute for Education and Youth
Hálova 6, 851 01 Bratislava, Slovakia
E-mail: anton.sirota@stuba.sk|Phone: +421 907 473 367

Dr. Martin Putala|Department of Organic Chemistry
Faculty of Natural Sciences
Comenius University, Bratislava, Ilkovičova 6, Slovakia
E-mail: putala@fns.uniba.sk|Phone: +421 918 669 092