IROC IX was the ninth year of IROC competition, which took place in 1985. It saw the use of the Chevrolet Camaro in all races, was the second straight season that television coverage was on CBS, and continued the format introduced in IROC VIII. Race one took place on the Daytona International Speedway, race two took place at Mid-Ohio, race three was rained out at Talladega Superspeedway, and race four concluded the year at Michigan International Speedway. Harry Gant won the championship and $158,200 in a tie-breaker with Darrell Waltrip.

The roster of drivers and final points standings were as follows:

Friday, February 15, 1985

(5) Indicates 5 bonus points added to normal race points scored for leading the most laps.
(3) Indicates 3 bonus points added to normal race points scored for leading the 2nd most laps
(2) Indicates 2 bonus points added to normal race points scored for leading the 3rd most laps.

Average speed: 182.278 mph (293.348 km/h)
Cautions: 1 (Lap 15, Tom Gloy accident in the tri-oval.)
Margin of victory: 3 sec
Lead changes: 3

Friday, June 8, 1985

(5) Indicates 5 bonus points added to normal race points scored for leading the most laps.
(3) Indicates 3 bonus points added to normal race points scored for leading the 2nd most laps
(2) Indicates 2 bonus points added to normal race points scored for leading the 3rd most laps (Did not occur in this race so not awarded).

Average speed: 84.363 mph (135.769 km/h)
Cautions: none
Margin of victory: 2.4 sec
Lead changes: 1