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. The Mexican team featured three Olympic medalists from Sydney: race walkerNoé Hernández, taekwondo jin Víctor Estrada, and diver Fernando Platas, who reprised his role to carry the national flag for the second time in the opening ceremony, after winning the silver in men's springboard. Along with Platas, race walkers Miguel Ángel Rodríguez and Germán Sánchez officially made their fourth Olympic appearance as the most experienced members of the team. Meanwhile, show jumper Gerardo Tazzer, who helped the Mexicans claim the bronze at the 1980 Summer Olympics in Moscow, sought his fourth Olympic bid in Athens after a sixteen-year absence, and was also the oldest athlete of the team at age 52. Mexico left Athens with a total of four medals, failing to win a gold for the first time since 1996. Half of these medals were awarded to the athletes in taekwondo. Sprinter Ana Guevara set the nation's historical milestone as the first ever female Mexican to claim an Olympic silver medal in track and field. Meanwhile, Belem Guerrero claimed a silver for the first time in the nation's Olympic cycling history, since the 1984 Summer Olympics in Los Angeles, since José Youshimatz took home the bronze in the men's points race.
Mexican rowers qualified the following boats: ;Women Qualification Legend: FA=Final A ; FB=Final B ; FC=Final C ; FD=Final D ; FE=Final E ; FF=Final F ; SA/B=Semifinals A/B; SC/D=Semifinals C/D; SE/F=Semifinals E/F; QF=Quarterfinals; R=Repechage
Sailing
Mexican sailors have qualified one boat for each of the following events. ;Men ;Women M = Medal race; OCS = On course side of the starting line; DSQ = Disqualified; DNF = Did not finish; DNS= Did not start; RDG = Redress given
Shooting
One Mexican shooter qualified to compete in the following events: ;Men
Swimming
Mexican swimmers earned qualifying standards in the following events : ;Men ;Women
Synchronized swimming
Two Mexican synchronized swimmers qualified a spot in the women's duet.
Taekwondo
Three Mexican taekwondo jin qualified for the following events.
Triathlon
Two Mexican triathletes qualified for the following events.
