2004 Cal Poly Mustangs football team
The 2004 Cal Poly Mustangs football team represented California Polytechnic State University, San Luis Obispo as member of the Great West Conference during the 2004 NCAA Division I-AA football season. Led by fourth-year head coach Rich Ellerson, Cal Poly compiled an overall record of 9–2 with a mark of 4–1 in conference play, winning the GWC title. The team outscored its opponents 336 to 183 for the season. The Mustangs played home games at Mustang Stadium in San Luis Obispo, California.
Cal Poly was a charter member of the newly-formed GWC. The Mustangs competed as an independent the previous eight seasons.
Team players in the NFL
The following Cal Poly Mustang players were selected in the 2005 NFL draft.| Player | Position | Round | Overall | NFL team |
| Jordan Beck | Linebacker | 3 | 90 | Atlanta Falcons |