2004 Grand Prix de Tennis de Lyon – Singles

Rainer Schüttler was the defending champion, but lost in the first round this year.

Robin Söderling won the tournament, beating Xavier Malisse 6–2, 3–6, 6–4 in the final.

Seeds
• # Nicolás Massú (first round)

• # 🇩🇪 Rainer Schüttler (first round)

• # 🇪🇸 Juan Carlos Ferrero (second round)

• # 🇸🇪 Joachim Johansson (quarterfinals)

• # 🇪🇸 Tommy Robredo (first round)

• # 🇸🇰 Dominik Hrbatý (first round)

• # 🇺🇸 Vincent Spadea (semifinals)

• # Mario Ančić (first round, retired due to a shoulder injury)