South Africa competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's sixteenth overall and fourth consecutive appearance at the Summer Olympics in the post-apartheid era. The South African Sports Confederation and Olympic Committee (SASCOC) sent a total of 106 athletes to the Games, 66 men and 40 women, to compete in 19 sports. Field hockey was the only team-based sport in which South Africa had its representation at these Games. There was only a single competitor in archery, canoeing, diving, artistic and rhythmic gymnastics, judo, sailing, shooting, taekwondo, and wrestling.
Puerto Rico competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's fifteenth consecutive appearance at the Olympics.
Kazakhstan competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's third appearance at the Summer Olympics in the post-Soviet era.
Russia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's third consecutive appearance at the Summer Olympics as an independent nation. The Russian Olympic Committee sent a total of 446 athletes to the Games, 244 men and 202 women, to compete in all sports, except baseball, field hockey, football, and softball.
China competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's ninth appearance at the Summer Olympics since its debut in 1952. A total of 384 Chinese athletes, 136 men and 248 women, were selected by the Chinese Olympic Committee to compete in 28 sports. For the third time in its Olympic history, China was represented by more female than male athletes.
Spain competed at the 2004 Summer Olympics in Athens, Greece, from August 13 to 29, 2004. This nation has competed in every Summer Olympic Games since its official debut in 1920. Spain, however, boycotted two editions, the 1936 Summer Olympics in Nazi Germany, and the 1956 Summer Olympics in Melbourne, as a protest to the Soviet invasion of Hungary. The Spanish Olympic Committee sent the nation's third largest delegation in history to the Games. A total of 317 athletes, 177 men and 140 women, competed in 26 sports.
South Korea competed at the 2004 Summer Olympics in Athens, from 13 to 29 August 2004. This was the nation's fourteenth appearance at the Olympics, except the 1980 Summer Olympics in Moscow because of its support for the United States boycott. The Korean Olympic Committee sent the nation's smallest delegation to the Games since 1992. A total of 264 athletes, 145 men and 119 women, competed in 25 sports.
The Netherlands competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Dutch athletes have competed in every Summer Olympic games since its official debut in 1908. Netherlands, however, boycotted the 1956 Summer Olympics in Melbourne, because of the Soviet invasion of Hungary. The Netherlands National Olympic Committee sent a total of 210 athletes to the Games, 134 men and 76 women, to compete in 21 sports. Baseball, field hockey, and men's volleyball were the only team-based sports in which the Netherlands had its representation at these Games. There was only a single competitor in women's fencing.
Israel competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. It was the nation's thirteenth appearance at the Summer Olympics.
Nigeria competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's thirteenth appearance at the Olympics, except the 1976 Summer Olympics in Montreal, because of the African boycott. Nigerian Olympic Committee sent a total of 72 athletes, 24 men and 48 women, to the Games to compete in 10 sports. For the first time in its Olympic history, Nigeria was represented by more female than male athletes. Women's basketball and women's football were the only team-based sports in which Nigeria had its representation at these Games. There was only a single competitor in men's freestyle wrestling.
Athletes from Iran competed at the 2000 Summer Olympics in Sydney, Australia.
Iran sent a team to compete at the 2008 Summer Olympics in Beijing, China. In total 55 Iranian athletes went to Beijing, including three women. These Olympics are regarded as less successful than their previous Games, as Iran only achieved one gold and one bronze medal.
The United States competed at the 2004 Summer Olympics in Athens, Greece. 533 competitors, 279 men and 254 women, took part in 254 events in 31 sports.
Egypt competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. Since the nation's debut in 1912, Egyptian athletes had appeared in every edition of the Summer Olympic Games except 1932 and 1980, joining the United States-led boycott in the latter.
Dominican Republic competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's fourteenth consecutive appearance at the Summer Olympics.
Gabon competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's tenth appearance at the Olympics.
Libya competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's eleventh appearance at the Olympics since its debut at the 1964 Summer Olympics in Tokyo; seven of them were represented by the Libyan athletes under the name Libyan Arab Jamahiriya.
The Democratic Republic of the Congo competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's tenth appearance at the Summer Olympics since its debut in 1968, although it had previously competed in four editions under the name Zaire.
Mali competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. Since the nation made its debut in 1964, Malian athletes had appeared in every edition of the Summer Olympic Games, with the exception of the 1976 Summer Olympics in Montreal because of the African boycott.
Costa Rica competed at the 2020 Summer Olympics in Tokyo. Originally scheduled to take place from 24 July to 9 August 2020, the Games were postponed to 23 July to 8 August 2021, because of the COVID-19 pandemic. It was the nation's sixteenth appearance at the Summer Olympics, since its debut in 1936.
