| 2004 Siebel Open | |
|---|---|
| Date | February 9–15 |
| Edition | 116th |
| Category | International Series |
| Draw | 32S / 16D |
| Prize money | $355,000 |
| Surface | Hard / indoor |
| Location | San Jose, U.S. |
| Venue | HP Pavilion at San Jose |
| Champions | |
| Singles | |
 Andy Roddick | |
| Doubles | |
| James Blake / Mardy Fish | |
The 2004 Siebel Open was a men's tennis tournament played on indoor hard courts at the HP Pavilion at San Jose in San Jose, California in the United States that was part of the International Series of the 2004 ATP Tour. The tournament ran from February 9 through February 15, 2004. First-seeded Andy Roddick won the singles title.