The 2004 Gerry Weber Open was a men's tennis tournament played on outdoor grass courts. It was the 12th edition of the Gerry Weber Open, and was part of the International Series of the 2004 ATP Tour. It took place at the Gerry Weber Stadion in Halle, North Rhine-Westphalia, Germany, from 7 June through 14 June 2004. First-seeded Roger Federer won his second consecutive singles title at the event.
See main article: 2004 Gerry Weber Open – Singles. Roger Federer defeated Mardy Fish 6–0, 6–3
See main article: 2004 Gerry Weber Open – Doubles. Leander Paes / David Rikl defeated Tomáš Cibulec / Petr Pála 6–2, 7–5