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 sent 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.
Japan competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Japanese athletes have competed at every Summer Olympic Games in the modern era since 1912 except for two editions; it was not invited to the 1948 Summer Olympics in London for its role in World War II, and was also part of the US-led boycott of the 1980 Summer Olympics in Moscow. The Japanese Olympic Committee sent a total of 306 athletes, 139 men and 167 women, to compete in 27 sports. For the first time in its Olympic history, Japan was represented by more female than male athletes.
Portugal competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Portuguese athletes have competed at every Summer Olympic Games in the modern era since 1912. The Olympic Committee of Portugal sent the nation's second-largest team to the Games. A total of 81 athletes, 64 men and 17 women, were selected by the committee to participate in 15 sports. Men's football was the only team-based sport in which Portugal had its representation at these Games. There was only a single competitor in badminton, canoeing, equestrian, artistic and trampoline gymnastics, triathlon, and wrestling, which made its official Olympic comeback after an eight-year absence.
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.
Mexico competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's twentieth appearance at the Olympics, since its debut in 1900. Comité Olímpico Mexicano sent the nation's largest delegation to the Games since 1992. A total of 109 athletes, 59 men and 50 women, competed in 20 sports. Football was the only team-based sport in which Mexico had its representation in these Olympic Games. There was only a single competitor in fencing, shooting, and weightlifting.
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.
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.
Brazil competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's nineteenth appearance at the Summer Olympics, excluding the 1928 Summer Olympics in Amsterdam. The Brazilian Olympic Committee sent the nation's largest ever delegation in history to the Games. A total of 243 athletes, 124 men and 119 women, competed in 24 sports.
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.
Argentina competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's twenty-first appearance at the Olympic Games, except for three different editions. Argentina did not attend the 1904 Summer Olympics in St. Louis, the 1912 Summer Olympics in Stockholm, and the 1980 Summer Olympics in Moscow, because of its support for the United States-led boycott. The sailor Carlos Espínola was the nation's flag bearer at the opening ceremony. 152 competitors, 106 men and 46 women, took part in 86 events in 22 sports.
Serbia and Montenegro competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Previously known as the Federal Republic of Yugoslavia, this was the nation's third and last joint appearance at the Summer Olympics before Serbia and Montenegro became separated independent states in 2006. The Olympic Committee of Serbia and Montenegro sent a total of 85 athletes to the Games, 78 men and 7 women, to compete in 14 sports. Men's basketball, football, volleyball, and water polo were the only team-based sports in which Serbia and Montenegro had its representation at these Games. There was only a single competitor in road cycling, judo, tennis, and wrestling.
Tunisia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's eleventh appearance at the Olympics, except the 1980 Summer Olympics in Moscow because of its partial support to the United States boycott.
Serbia competed at the 2008 Summer Olympics in Beijing, People's Republic of China. The country returned under the name Serbia after 96 years, previously competing under the names Yugoslavia (1920–1988), Independent Olympic Participants (1992), Yugoslavia (1996–2002) and Serbia and Montenegro (2004–2006).
Germany competed at the 2008 Summer Olympics in Beijing, People's Republic of China. A total of 439 athletes were nominated to participate in the Games. The German Olympic Sports Confederation nominated athletes on 29 May, 23 June and 15 July 2008. Reaching the qualification standard set by the relevant sport's international governing body did not automatically mean that the athlete was nominated for Beijing, as the DOSB had stricter qualification standards. An athlete needed to have a somewhat realistic chance for a top 12 position. An exception to this are the team events, as the number of competing teams is already very limited through the IOC standards, and a chance for a respective place is already given by the qualification.
Italy competed at the 2008 Summer Olympics, held in Beijing, China. The country sent a delegation of 344 athletes to compete.
Brazil sent a delegation to compete at the 2008 Summer Olympics in Beijing, China, in August 2008. Brazilian athletes have competed in every Summer Olympic Games since 1920, except the 1928 Summer Olympics. The country is represented by the Brazilian Olympic Committee. Brazil headed to the Beijing Games with its largest Olympic delegation at the time, 277 athletes, including 132 women.
China was the host nation of the 2008 Summer Olympics. China was represented by the Chinese Olympic Committee (COC), and the team of selected athletes were officially known as Team China.
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.
Australasia (1908–1912)
