NASCAR rescheduled the race for Monday at noon Eastern.
The forecast didn't look good from the start, but because the facility has lights, NASCAR waited all day for a window to dry the track. Officials got the window and had the track almost dry, but the sky opened again roughly six hours after the scheduled start.
"We appreciate the fans hanging in there with us and we know that rain presents an issue that nobody has much control over and it's uncomfortable," NASCAR president Mike Helton said earlier Sunday. "But I think it's in everybody's best interest to try to get it in and we've got time to wait and see."
Time ran out about 8 p.m., with NASCAR releasing teams after the almost-dry track was soaked by a heavy rain. It marks the first Chase race since the championship series debuted in 2004 to be postponed.
The only Chase race that failed to be run to its conclusion was the 2007 event at Kansas, which was called for darkness after a rain delay halted action in the middle of the event. The race resumed, but ran only 210 of the scheduled 267 laps.
Matt Kenseth will start from the pole at Chicagoland when the race goes off on Monday, and he said he didn't think the full day of rain would present many problems for drivers.
"I think it will change the first 40 or 50 laps until the track gets rubbered up again, then I think it will be similar to what it has been all weekend," Kenseth said.
NASCAR previously had scheduled a competition caution 30 laps into the race, and Kenseth said the pause will allow teams to "get the tires off and take a look at it, and by then the track should be pretty well rubbered in and hopefully back to similar conditions we practiced in."
Six Chase drivers are starting in the top 10, with Kevin Harvick the lowest qualifying Chase driver at 30th.
This is the second time in three weeks the race has been disrupted by rain. The Sept. 4 race at Atlanta was delayed by two days by heavy rains. When the event did go off, it was stopped or slowed several times by brief showers.
As drivers waited out the rain this time, the lone excitement at the track was when the pace car inexplicably went missing. NASCAR officials made several calls before determining an intern from Chicagoland Speedway had taken the car to be washed — while it was raining.
Earlier Sunday, team owner Richard Childress spoke briefly about his recent election into the International Motorsports Hall of Fame. He'll be the headliner of the class being inducted in May at Talladega Superspeedway.
"I remember walking through the Hall of Fame when it was just done and thinking, 'Man, it would be neat to one day get in this,'" Childress said. "I'm still in shock."
Childress drove in his first Cup race in 1969, and compiled 75 top-10 finishes in 285 races over the course of his driving career. His mark, though, was made as owner of Richard Childress Racing.
A partnership with Dale Earnhardt that began in 1981 helped RCR win six championships as an owner from 1986-94.
"From the time we ran those first 10 races I knew we had something special," Childress said. "He's the reason I'm here really today and I'll always be thankful to him for that."
RCR also has won five Nationwide titles and one in the Trucks Series. Childress driver Harvick opens the Chase tied with Kyle Busch for the points lead.