2004 Australian Open – Men's singles

Roger Federer defeated Marat Safin in the final, 7–6(7–3), 6–4, 6–2 to win the men's singles tennis title at the 2004 Australian Open. It was his first Australian Open title and second major title overall. With the win, Federer gained the world No. 1 ranking for the first time in his career, and would hold the position for a record 237 consecutive weeks.

Andre Agassi was the defending champion, but lost in the semifinals to Safin. This ended his streak of 26 straight match wins at the Australian Open.

This was the only time in Andy Roddick's career where he was seeded first at a major. He lost to Safin in the quarterfinals.

13 seeded players lost in the first round, the most at a major since the 32-seed draw was adopted at the 2001 Wimbledon Championships.

Seeds
• # 🇺🇸 Andy Roddick (quarterfinals)

• # Roger Federer (champion)

• # 🇪🇸 Juan Carlos Ferrero (semifinals)

• # 🇺🇸 Andre Agassi (semifinals)

• # 🇦🇷 Guillermo Coria (first round)

• # 🇩🇪 Rainer Schüttler (first round)

• # 🇪🇸 Carlos Moyá (withdrew due to ankle injury)

• # 🇦🇷 David Nalbandian (quarterfinals)

• # 🇫🇷 Sébastien Grosjean (quarterfinals, retired)

• # 🇦🇺 Mark Philippoussis (fourth round)

• # 🇬🇧 Tim Henman (third round)

• # 🇨🇱 Nicolás Massú (first round)

• # 🇹🇭 Paradorn Srichaphan (fourth round)

• # 🇨🇿 Jiří Novák (third round)

• # 🇦🇺 Lleyton Hewitt (fourth round)

• # 🇳🇱 Sjeng Schalken (fourth round)

• # 🇳🇱 Martin Verkerk (first round)

• # 🇲🇦 Younes El Aynaoui (first round)

• # 🇧🇷 Gustavo Kuerten (third round)

• # 🇪🇸 Tommy Robredo (first round)

• # 🇺🇸 Mardy Fish (first round)

• # 🇦🇷 Agustín Calleri (second round)

• # 🇪🇸 Félix Mantilla (first round)

• # 🇧🇾 Max Mirnyi (first round)

• # 🇸🇪 Jonas Björkman (first round)

• # 🇪🇸 Albert Costa (third round)

• # 🇺🇸 Taylor Dent (third round)

• # 🇪🇸 Feliciano López (first round)

• # 🇺🇸 Vince Spadea (first round)

• # 🇫🇷 Arnaud Clément (first round)

• # 🇿🇦 Wayne Ferreira (third round)

• # 🇺🇸 Robby Ginepri (fourth round)