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.
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.
Ukraine 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 in the post-Soviet era. The National Olympic Committee of Ukraine sent the nation's largest ever delegation to these Games. A total of 240 athletes, 125 men and 115 women, took part in 21 sports. Women's handball was the only team-based sport in which Ukraine had its representation at these Games for the first time. There was only a single competitor in modern pentathlon and taekwondo.
Cuba competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's seventeenth appearance in the Olympics, except for some editions. Cuban athletes did not attend in two Olympic Games, where they joined the Soviet and North Korean boycott. Cuban Olympic Committee sent the nation's smallest delegation to the Games since 1972. A total of 151 athletes, 97 men and 54 women, competed in 18 sports.
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.
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.
Bulgaria competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's seventeenth appearance at the Summer Olympics, except for 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. The Bulgarian Olympic Committee sent 95 athletes, 49 men and 46 women, to compete in 19 sports. Shooting champion and four-time Olympian Mariya Grozdeva became the nation's first ever female flag bearer in the opening ceremony.
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.
Czech Republic 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 after gaining its independence from the former Czechoslovakia. The Czech Olympic Committee sent the nation's largest team to the Games since the post-Czechoslovak era. A total of 142 athletes, 80 men and 62 women, competed in 19 sports; the nation's team size was roughly denser from Sydney by one sixth of the athletes. Women's basketball was the only team-based sport in which the Czech Republic had its representation at these Olympic Games. There was only a single competitor in equestrian, artistic and trampoline gymnastics, judo, and weightlifting.
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.
Lithuania competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's sixth appearance at the Summer Olympics. The National Olympic Committee of Lithuania sent the nation's smallest delegation to the Games since the 1992 Summer Olympics in Barcelona. A total of 59 athletes, 47 men and 12 women, competed in 13 sports, including the men's basketball team as the nation's team-based sport.
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.
