Algeria competed at the 2004 Summer Olympics in Athens, Greece from 13 to 29 August 2004. It first competed in the Olympics in 1964, and entered the 2004 Athens Games having won a total of twelve medals — including one gold, one silver, and three bronze medals at the 2000 Summer Olympics. These medals were in athletics and boxing. 61 competitors, 46 men and 15 women, took part in 57 events in 10 sports.
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.
France competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. French athletes have competed in every Summer Olympic Games of the modern era. The French Olympic Committee sent a total of 308 athletes to the Games, 195 men and 113 women, to compete in 25 sports.
India competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. The Indian Olympic Association sent a total of 73 athletes, 48 men, and 28 women, to compete in 14 sports. Men's field hockey was the only team-based sport in which India had its representation in these Olympic games. As a pleasant surprise, the shooting team came successful with a silver medal, the winner being Capt. Rajyavardhan Singh Rathore. He was the first Indian to win an individual silver medal.
Indonesia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's twelfth appearance at the Olympics, excluding the 1964 Summer Olympics in Tokyo, and the 1980 Summer Olympics in Moscow because of the United States boycott. Krisna Bayu was originally the flag bearer, however the role was later done by Christian Hadinata because Bayu was suffering from flu at the eve of opening ceremony.
Poland competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's eighteenth appearance at the Summer Olympics, except the 1984 Summer Olympics in Los Angeles, because of the Soviet boycott. The Polish Olympic Committee sent a total of 194 athletes to the Games, 132 men and 62 women, to compete in 21 sports. Men's volleyball was the only team-based sport in which Poland had its representation in these Olympic Games. There was only a single competitor in women's taekwondo.
Denmark competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004.
Romania competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Romanian athletes have competed at every Summer Olympic Games since its official debut in 1924, missing only two editions, including the 1948 Summer Olympics. The Romanian Olympic and Sports Committee sent the nation's smallest team to the Games since the 1988 Summer Olympics in Seoul. A total of 108 athletes, 50 men and 58 women, had competed in 16 different sports, most notably in artistic gymnastics and rowing. For the third time in Olympic history, Romania was again represented by more female than male athletes.
Slovenia 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 Slovenian Olympic Committee sent the nation's largest ever delegation to the Games in Olympic history. A total of 79 athletes, 56 men and 23 women, competed in 10 sports. For the second consecutive time, men's handball was the only team-based sport in which Slovenia had its representation at these Games.
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.
Peru competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's fifteenth appearance at the Olympics, except the 1952 Summer Olympics in Helsinki.
Slovakia 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 since the post-Czechoslovak era. The Slovak Olympic Committee sent a total of 64 athletes to the Games, 48 men and 16 women, to compete in 11 sports. There was only a single competitor in artistic and trampoline gymnastics and sailing.
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.
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 full support to the United States boycott.
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.
Switzerland competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Swiss athletes competed at every Summer Olympic Games in the modern era, except when they boycotted the 1956 Summer Olympics in Melbourne as a protest to the Soviet invasion of Hungary. The Swiss Olympic Association sent a total of 98 athletes to the Games, 59 men and 39 women, to compete in 18 sports.
Vietnam competed at the 2004 Summer Olympics in Athens, Greece from 13 to 29 August 2004.
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.
Bulgaria competed at the 2012 Summer Olympics in London, United Kingdom from 27 July to 12 August 2012. It was the nation's nineteenth appearance at the Summer Olympics, having missed the Olympics on three occasions, including the 1948 Summer Olympics in London due to the nation's role in World War II and 1984 Summer Olympics in Los Angeles because of the Soviet boycott. Despite this being London's third Olympic Games, this was the first time a Bulgarian team appeared at a London Olympics. The Bulgarian Olympic Committee sent the nation's smallest delegation to the Games, tying the record with Helsinki in 1952, and with Tokyo in 1964. A total of 63 athletes, 36 men and 27 women, competed in 16 sports. Men's volleyball was the only team event in which Bulgaria was represented in these Olympic games. There was only a single competitor in badminton, sprint canoeing, fencing, and judo.
