The 2004 Grand Prix de Tennis de Lyon was a men's tennis tournament played on indoor hard courts. It was played at the Palais des Sports de Gerland in Lyon in France and was part of the 2004 ATP Tour. The tournament took place from October 4 through October 11, 2004. Robin Söderling won the singles title.
Robin Söderling defeated Xavier Malisse 6–2, 3–6, 6–4
- It was Söderling's only title of the year and the 1st of his career.
Jonathan Erlich / Andy Ram defeated Jonas Björkman / Radek Štěpánek 7–6(7–2), 6–2
- It was Erlich's only title of the year and the 4th of his career. It was Ram's only title of the year and the 4th of his career.