The thirteenth year of IROC competition took place in 1989. IROC XIII saw the use of the Chevrolet Camaro in all races for the final year, and continued the format introduced in IROC VIII. Race one took place on the Daytona International Speedway, race two took place at Nazareth Speedway, race three ran at Michigan International Speedway, and race four concluded the year at Watkins Glen International. Terry Labonte won the series championship, and took home $204,900 for his efforts.
The roster of drivers and final points standings were as follows:
| Position | Driver | Points | Winnings | Series |
|---|---|---|---|---|
| 1 | Terry Labonte | 72 | $204,900 | NASCAR Winston Cup |
| 2 | Al Unser, Jr. | 60 | $92,500 | CART |
| 3 | Rusty Wallace | 58 | $66,200 | NASCAR Winston Cup |
| 4 | Dale Earnhardt | 57 | $58,900 | NASCAR Winston Cup |
| 5 | Scott Pruett | 51 | $55,700 | IMSA Camel GT |
| 6 | Bill Elliott | 38 | $52,000 | NASCAR Winston Cup |
| 7 | A.J. Foyt | 36 | $54,000 | CART |
| 8 | Danny Sullivan | 35 | $49,400 | CART |
| 9 | Hurley Haywood | 31 | $46,000 | SCCA Trans-Am Series |
| 10 | Geoff Brabham1 | 24 | $44,400 | IMSA Camel GT |
| 11 | Rick Mears1 | 24 | $42,100 | CART |
| 12 | Richard Petty | 16 | $40,400 | NASCAR Winston Cup |