Offseason
- November 3, 2003: Billy Wagner was traded by the Houston Astros to the Philadelphia Phillies for Brandon Duckworth, Taylor Buchholz, and Ezequiel Astacio.
- December 16, 2003: Andy Pettite was Signed as a Free Agent with the Houston Astros.
- January 19, 2004: Roger Clemens signed as a Free Agent with the Houston Astros.
- March 25, 2004: Mike Lamb was traded by the New York Yankees to the Houston Astros for Juan DeLeon (minors).
Read more about this topic: 2004 Houston Astros Season