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.
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.
Turkey competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Turkish athletes have competed at every Summer Olympic Games since its debut in 1908. Turkey did not attend the 1920 Summer Olympics in Antwerp, the 1932 Summer Olympics in Los Angeles at the period of Great Depression, and the 1980 Summer Olympics in Moscow because of the United States boycott. The Turkish Olympic Committee sent the nation's largest delegation to the Games. A total of 65 athletes, 45 men and 20 women, competed in 10 sports. There was only a single competitor in shooting and taekwondo.
Georgia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Georgian National Olympic Committee (GNOC) sent the nation's smallest delegation to the Games since the post-Soviet era. A total of 32 athletes, 26 men and 6 women, competed in 10 different sports.
Tajikistan competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004.
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.
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 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.
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.
Mongolia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's tenth appearance at the Olympics, except the 1984 Summer Olympics in Los Angeles, because of its partial support to the Soviet boycott.
Colombia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's sixteenth appearance at the Olympics, except the 1952 Summer Olympics in Helsinki.
The Dominican Republic competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. Francia Jackson was chosen to be the flag bearer at the games instead of the previous chosen athlete Félix Sánchez, who won the nation's first ever Olympic gold medal.
Venezuela 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, since its debut in 1948. A total of 48 athletes, 33 men and 15 women, competed in 15 sports.
Namibia 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 Olympics.
Kyrgyzstan competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's third appearance at the Olympics in the post-Soviet era.
Senegal 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.
Palau competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004.
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.
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.
Moldova competed at the 2004 Summer Olympics in Athens, from 13 to 29 August 2004. This was the nation's third consecutive appearance at the Summer Olympics in the post-Soviet era.
Armenia competed at the 2004 Summer Olympics in Athens, Greece from 13 to 29 August 2004.
Russian Empire (1900–1912)
Soviet Union (1952–1988)
Unified Team (1992)
