2004 Brasil Open – Singles

Sjeng Schalken was the defending champion but did not compete that year.

Gustavo Kuerten won in the final 3–6, 6–2, 6–3 against Agustín Calleri.

Seeds
• # 🇪🇸 Carlos Moyá (first round)

• # Nicolás Massú (first round)

• # 🇧🇷 Gustavo Kuerten (champion)

• # 🇦🇷 Agustín Calleri (final)

• # 🇦🇷 Mariano Zabaleta (first round)

• # 🇪🇸 Félix Mantilla (first round)

• # 🇦🇷 Gastón Gaudio (second round)

• # 🇦🇷 Juan Ignacio Chela (quarterfinals)