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.
The Mongolian National Olympic Committee sent a total of 20 athletes, 13 men and 7 women, to compete in 7 different sports, tying its delegation count with Sydney four years earlier. In the wake of Munkhbayar Dorjsuren's transfer to the German team, three Mongolian athletes had previously competed in Sydney, including shooter Otryadyn Gündegmaa in the women's pistol events. Judoka and world champion Damdinsürengiin Nyamkhüü was appointed by the committee to become Mongolia's flag bearer in the opening ceremony, dressed in a traditional costume.
After failing to achieve a single Olympic medal from Sydney, Mongolia left Athens with only a bronze from twenty-year-old judoka Khashbaataryn Tsagaanbaatar on the first day of the Games.
Mongolian athletes have so far achieved qualifying standards in the following athletics events (up to a maximum of 3 athletes in each event at the 'A' Standard, and 1 at the 'B' Standard).
Mongolia sent one lightweight boxer to the 2004 Olympics.
Eight Mongolian judoka (six men and two women) qualified for the 2004 Summer Olympics, its largest contingent in any sport, and it was rewarded with its only medal of the Games. Khashbaataryn Tsagaanbaatar won his first three matches in less than five minutes, progressing to the semifinals, where he lasted less than thirty seconds against his Japanese opponent. In the bronze medal match, there were no scores in the five-minute period, so another period was played, and Tsagaanbaatar scored with less than a minute-and-a-half remaining to win the bronze.
One Mongolian shooter qualified to compete in the following events:
Mongolia has qualified a single weightlifter.