This year's revived Arlington Million will carry boosted prize money of US2million (£1.2million).
It will be part of an "international festival" when it is run after a two-year break on August 19th, together with a US500,000 (£300,000) fillies' race and a US400,000 (£240,000) event for three-year-olds - all three on turf.
The mile-and-a-quarter race, which became the first in the world to offer a US1million prize when it was launched in 1981, will also form part of the Emirates world series of racing.
Arlington racetrack near Chicago has been closed since 1997.
But chief executive officer Scott Mordell said: "We feel doubling the purse of the Million, America's first million-dollar horserace, is an appropriate move for the year 2000.
"It ensures the Million's premier status in the industry and confirms the optimism all of us in Illinois have about the future of racing here."
The Million was won by British horses Tolomeo (trained by Luca Cumani) in 1983 and Teleprompter (Bill Watts) in 1985.
