The 2003 Gateway 100 was Round 8 of the 2003 IRL Infiniti Pro Series. The event was held at Gateway in Illinois, United States on 9 August 2003. Jeff Simmons was the race winner.
Gateway 100 Race Result
| Pos. | No. | Driver | Chassis | Engine | Tire | Laps | Laps Led | Status | Started | Points |
|---|---|---|---|---|---|---|---|---|---|---|
| 1 | 20 | Jeff Simmons | Dallara | Infiniti | Firestone | 80 | 2 | Running | 3 | 50 |
| 2 | 92 | Cory Witherill | Dallara | Infiniti | Firestone | 80 | 0 | Running | 6 | 40 |
| 3 | 5 | Arie Luyendyk Jr. | Dallara | Infiniti | Firestone | 80 | 0 | Running | 7 | 35 |
| 4 | 14 | Ed Carpenter | Dallara | Infiniti | Firestone | 80 | 0 | Running | 5 | 32 |
| 5 | 9 | Tom Wood | Dallara | Infiniti | Firestone | 80 | 0 | Running | 2 | 30 |
| 6 | 91 | Aaron Fike | Dallara | Infiniti | Firestone | 80 | 0 | Running | 9 | 28 |
| 7 | 33 | Paul Dana | Dallara | Infiniti | Firestone | 79 | 0 | Running | 10 | 26 |
| 8 | 25 | G.J. Mennen | Dallara | Infiniti | Firestone | 79 | 0 | Running | 8 | 24 |
| DNF | 4 | Mark Taylor | Dallara | Infiniti | Firestone | 78 | 78 | Accident | 4 | 24 |
| DNF | 99 | Brandon Erwin | Dallara | Infiniti | Firestone | 78 | 0 | Accident | 1 | 20 |
| DNF | 36 | Thiago Medeiros | Dallara | Infiniti | Firestone | 43 | 0 | Electrical | 11 | 19 |
| DNF | 27 | Gary Peterson | Dallara | Infiniti | Firestone | 0 | 0 | Did Not Start | 12 | 18 |
| DNF | 24 | Moses Smith | Dallara | Infiniti | Firestone | 0 | 0 | Did Not Start | 13 | 17 |