The 2003 California 100 was Round 11 of the 2003 IRL Infiniti Pro Series. The event was held at Auto Club Speedway in Fontana, California, United States on 20 September 2003. Mark Taylor was the race winner.
California 100 Race Result
| Pos. | No. | Driver | Chassis | Engine | Tire | Laps | Laps Led | Status | Started | Points |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 4 | Mark Taylor | Dallara | Infiniti | Firestone | 50 | 50 | Running | 1 | 52 |
| 2 | 14 | Ed Carpenter | Dallara | Infiniti | Firestone | 50 | 0 | Running | 2 | 40 |
| 3 | 36 | Thiago Medeiros | Dallara | Infiniti | Firestone | 50 | 0 | Running | 4 | 35 |
| 4 | 25 | G.J. Mennen | Dallara | Infiniti | Firestone | 50 | 0 | Running | 6 | 32 |
| 5 | 24 | Billy Roe | Dallara | Infiniti | Firestone | 50 | 0 | Running | 10 | 30 |
| 6 | 91 | Aaron Fike | Dallara | Infiniti | Firestone | 50 | 0 | Running | 3 | 28 |
| 7 | 12 | Matt Beardsley | Dallara | Infiniti | Firestone | 50 | 0 | Running | 15 | 26 |
| 8 | 20 | Jeff Simmons | Dallara | Infiniti | Firestone | 50 | 0 | Running | 9 | 24 |
| 9 | 92 | Cory Witherill | Dallara | Infiniti | Firestone | 50 | 0 | Running | 7 | 22 |
| 10 | 5 | Arie Luyendyk Jr. | Dallara | Infiniti | Firestone | 50 | 0 | Running | 11 | 20 |
| 11 | 99 | Brad Pollard | Dallara | Infiniti | Firestone | 50 | 0 | Running | 8 | 19 |
| 12 | 9 | Taylor Fletcher | Dallara | Infiniti | Firestone | 50 | 0 | Running | 13 | 18 |
| 13 | 3 | Marty Roth | Dallara | Infiniti | Firestone | 50 | 0 | Running | 5 | 17 |
| 14 | 33 | Paul Dana | Dallara | Infiniti | Firestone | 49 | 0 | Running | 14 | 16 |
| DNF | 27 | Gary Peterson | Dallara | Infiniti | Firestone | 9 | 0 | Accident | 12 | 15 |