2004 French Open – Men's singles

Gastón Gaudio defeated Guillermo Coria in the final, 0–6, 3–6, 6–4, 6–1, 8–6 to win the men's singles tennis title at the 2004 French Open. It was his first and only major title, and he was the first Argentine to win a men's singles major since Guillermo Vilas at the 1979 Australian Open. Gaudio came from two sets down, saved two championship points, and twice broke Coria's serve when the latter was serving for the championship. This remains the most recent men's singles major to be won by an unseeded player.

Juan Carlos Ferrero was the defending champion, but was defeated in the second round by Igor Andreev: his first career loss at the French Open prior to the semifinals.

This was the first major where Roger Federer competed as the world No. 1. He lost in the third round to former No. 1 and three-time champion Gustavo Kuerten, his last pre-quarterfinal exit from a major until the 2013 Wimbledon Championships (a run of 36 quarterfinals or better in a row). Future 14-time champion Rafael Nadal withdrew prior to the tournament due to an ankle injury sustained in Estoril in April. This was the last time that none of the Big Three reached the round of 16 at a major until the 2024 US Open.

This was the first major in the Open Era to feature four Argentines in the quarterfinals, those being Gaudio, Coria, David Nalbandian, and Juan Ignacio Chela.

Wayne Ferreira matched Stefan Edberg's all-time record on his 54th consecutive major main draw appearance.

The first round match between Fabrice Santoro and Arnaud Clément was the then-longest match of the Open Era, lasting 6 hours and 33 minutes and played over two days. John Isner and Nicolas Mahut would later break this record with their first-round singles match at the 2010 Wimbledon Championships.