Judo at the 2004 Summer Olympics took place in the Ano Liossia Olympic Hall and featured 368 judoka competing for 14 gold medals with seven different weight categories in both the men's and women's competitions. Japan dominated the event by taking 8 gold and 2 silver medals.
Greece was the host country for the 2004 Summer Olympics in Athens, from 13 to 29 August 2004. As the progenitor nation and in keeping with tradition, Greek athletes have competed at every Summer Olympics in the modern era, alongside Australia, Great Britain, and Switzerland. The Hellenic Olympic Committee fielded a total of 426 athletes to the Games, 215 men and 211 women, and had achieved automatic qualification places in all sports, with the exception of men's and women's field hockey. It was also the nation's largest team ever in Summer Olympic history since the first modern Games were held in 1896.
Australia, the previous host of the 2000 Olympics at Sydney, competed at the 2004 Summer Olympics in Athens, Greece from 13 to 29 August 2004. Australian athletes have competed in every Summer Olympic Games of the modern era. The Australian Olympic Committee sent a total of 470 athletes to the Games to compete in 29 sports.
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.
Italy competed at the 2004 Summer Olympics in Athens, Greece, from the 13th to the 29th of August 2004. The country has competed at every Summer Olympic games in the modern era, except for the 1904 Summer Olympics in St. Louis. The Italian National Olympic Committee sent the nation's largest ever delegation in history to the Games. A total of 364 athletes, 229 men and 135 women, competed in 27 sports.
Germany competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's fourth consecutive appearance at the Summer Olympics after its reunification in 1990. The German Olympic Sports Confederation sent the nation's second largest delegation to the Games since its reunification. A total of 441 athletes, 250 men and 191 women, competed in 27 sports, and were nominated by DOSB at four occasions.
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 when it joined the Dutch-led boycott, 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, attending every Summer Olympics held during the country's existence up to that point with the exception of the 1980 Summer Olympics in Moscow because of its support for the United States-led 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.
New Zealand competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's twenty-second appearance at the Olympics since its debut in 1908 as part of Australasia. The New Zealand Olympic Committee sent a total of 148 athletes, 81 men, and 67 women to the Games to compete in 18 sports, surpassing a single athlete short of the record from Sydney four years earlier. Basketball and field hockey were the only team-based sports in which New Zealand had its representation at these Olympic Games. There was only a single competitor in archery, boxing, and fencing.
Hungary competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Hungarian athletes have competed at every Summer Olympic Games in the modern era, except the 1920 Summer Olympics in Antwerp, and the 1984 Summer Olympics in Los Angeles because of the Soviet boycott. The Hungarian Olympic Committee sent a total of 209 athletes to the Games, 119 men and 90 women, to compete in 20 sports. Water polo and handball were the only team-based sports in which Hungary had its representation in these Olympic Games. There was only a single competitor in road cycling and mountain biking.
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 Russian Federation competed at the 2008 Summer Olympics, held in Beijing, China, represented by the Russian Olympic Committee. Russia competed in all sports except baseball, field hockey, football, softball, and taekwondo. It ranked third in the medal table by the number of gold (24) and overall (60) medals. Russia also had 14 medals stripped for doping violations, the most of any nation at the 2008 Olympics, although in terms of gold medals it got a net positive of +1.
Chinese Taipei competed at the 2012 Summer Olympics in London, from 27 July to 12 August 2012. "Chinese Taipei" was the designated name used by Taiwan to participate in some international organizations and almost all sporting events, including the Olympic Games. Neither the common name "Taiwan" nor the official name "Republic of China" would be used due primarily to opposition from the People's Republic of China. This was the nation's eighth consecutive appearance at the Olympics.
The United States of America (USA) competed at the 2004 Summer Olympics in Athens, Greece. 533 competitors, 279 men and 254 women, took part in 254 events in 31 sports.
