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.
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.
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.
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.
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.
The Philippines competed at the 2004 Summer Olympics in Athens, 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.
Laos competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's sixth appearance at the Olympics, having attended every edition of the Olympiad since 1980 except the 1984 Summer Olympics in Los Angeles, because of the Soviet boycott.
Mauritius competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's sixth consecutive appearance at the Olympics.
Luxembourg competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. The nation has competed at every Olympic games for a century, except the 1932 Summer Olympics in Los Angeles.
Fiji competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004.
Guatemala competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's eleventh appearance at the Summer Olympics, excluding three occasions after its national debut at the 1952 Summer Olympics in Helsinki.
Singapore competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's thirteenth appearance at the Olympics, except for two different editions. Singapore was part of the Malaysian team at the 1964 Summer Olympics in Tokyo, but did not attend at the 1980 Summer Olympics in Moscow, because of its support for the United States boycott.
Jamaica competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's fourteenth appearance at the Summer Olympics as an independent nation, although it had previously appeared in the first four editions as a British colony, and as part of the West Indies Federation. The Jamaica Olympic Association sent a total of 47 athletes to the Games, 22 men and 25 women, to compete only in track and field, badminton, shooting, and swimming. For the second consecutive time in Olympic history, Jamaica was represented again by more female than male athletes.
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.
Latvia competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This was the nation's eighth appearance at the Summer 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.
Barbados competed at the 2004 Summer Olympics in Athens, Greece, from 13 to 29 August 2004. This nation marked its ninth appearance at the Olympics, except the 1980 Summer Olympics in Moscow because of the United States boycott.
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.
Malaysia competed at the 2016 Summer Olympics in Rio de Janeiro, Brazil, from 5 to 21 August 2016. This was the nation's fifteenth appearance at the Olympics, although it had previously competed in two other editions under the name Malaya. Tan Sri Mohamed Al-Amin Abdul Majid was the chef de mission of the national delegation at the Games.
North Borneo (1956)
