Australia 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.
The women's discus throw competition at the 2004 Summer Olympics in Athens was held at the Olympic Stadium on 20–21 August. It was originally planned to hold the discus throw at the Ancient Olympia Stadium, but it was discovered that the field was not large enough to accommodate the range of modern discus throwers, and would have posed a danger to spectators. As such, it was decided to move the discus throw and to hold the shot put at the ancient stadium, despite the fact that the shot put was not contested at the Ancient Olympic Games.
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.
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.
Belarus competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's fifth appearance at the Summer Olympics in the post-Soviet era. The Belarus Olympic Committee sent a total of 151 athletes to the Games, 82 men and 69 women, to compete in 22 sports.
Hong Kong competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. It was the territory's thirteenth appearance at the Olympics and, at the opening ceremony, its team was the last to enter the stadium before the host nation because of the use of the Greek alphabet.
Sweden competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This nation has competed at every Summer Olympic Games in the modern era, except for the 1904 Summer Olympics in St. Louis. The Swedish Olympic Committee sent the nation's smallest team to the Games since the 1976 Summer Olympics in Montreal. A total of 115 athletes, 62 men and 53 women, competed only in 20 different sports. Women's football was the only team-based sport in which Sweden had its representation at these Games. There was only a single competitor in boxing, diving, artistic gymnastics, judo, modern pentathlon, and rowing.
Norway competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's twenty-fourth appearance at the Summer Olympics, except for the 1904 Summer Olympics in St. Louis, and the 1980 Summer Olympics in Moscow, due to the country's support of the United States boycott. With the absence of women's football and handball teams, Norwegian Olympic and Paralympic Committee and Confederation of Sports sent the nation's smallest delegation to the Games since the 1968 Summer Olympics in Mexico City. A total of 53 athletes, 36 men and 17 women, competed only in 12 different sports. There was only a single competitor in badminton, swimming, taekwondo, weightlifting, and wrestling.
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.
Austria competed at the 2004 Summer Olympics in Athens, Greece from 13 to 29 August 2004. 74 competitors, 54 men and 20 women, took part in 56 events in 18 sports.
Croatia 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 since the post-Yugoslav era. The Croatian Olympic Committee sent the nation's smallest delegation to the Games since its debut in 1992. A total of 81 athletes, 66 men and 15 women, competed in 14 sports. Men's water polo, and men's handball were the only team-based sports in which Croatia had its representation in these Olympic Games.
Estonia 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.
Uruguay competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's eighteenth appearance at the Olympics, except the 1980 Summer Olympics in Moscow, because of its partial support to the United States boycott.
Uzbekistan 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 Olympics. The National Olympic Committee of the Republic of Uzbekistan sent a total of 70 athletes to the Games, 52 men and 18 women, to compete in 13 different sports, tying its delegation record with Sydney four years earlier. There was only a single competitor in road cycling, artistic and trampoline gymnastics, and table tennis.
Czech Republic competed at the 2012 Summer Olympics in London, United Kingdom, from 27 July to 12 August 2012. This was the nation's fifth appearance at the Summer Olympics after gaining its independence from the former Czechoslovakia. The Czech Olympic Committee sent a total of 133 athletes to the Games, 68 men and 65 women, to compete in 19 sports.
Ukraine competed at the 2012 Summer Olympics in London, from July 27 to August 12, 2012. This was the nation's fifth consecutive appearance at the Summer Olympics in the post-Soviet era. The National Olympic Committee of Ukraine sent a total of 238 athletes, split equally between men and women, to compete in 21 sports.
Zimbabwe competed at the 2012 Summer Olympics in London, UK from 27 July to 12 August 2012. This was the nation's ninth consecutive appearance at the Olympics, after gaining its independence from the former Rhodesia.
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.
Bohemia (1900–1912)
Czechoslovakia (1920–1992)
