At the 2005 Daytona Speedweeks, it was announced that DEI was looking at signing Matt Kenseth away from Roush Racing for a fourth team, sponsored by DeWalt tools. Kenseth signed the week before the Budweiser Shootout, giving DEI four top quality drivers under their roof.
The green flag waved with Dale Jarrett leading the field, but he lost the first lap to Jimmie Johnson and fell back through the field after a small bump from behind from defending Daytona 500 champion Dale Earnhardt, Jr.. Tony Stewart took the lead from Johnson on lap 4 and led 12 laps.
The first caution came out on lap 10 halfway through the first fuel run when Jimmie Johnson went too high and took out 12 cars, namely Matt Kenseth and Bobby Labonte, after picking up debris from the wreck, blew an engine almost at the exact same time. Scott Wimmer, who had only changed two tires, led when the race restarted. The second caution flew on lap 28 when Ricky Rudd spun out in the middle of the field, collecting five cars.
On lap 61, there came to the start of green-flag pit stops, with the Dodges coming in first, as they did not get as good fuel mileage as others. Earnhardt, Jr. was pushed by Jeff Burton coming into his pit stop, and had to back up to get out after his tires were changed, causing him to drop down through the field. There was a total of seven speeding violations on pit road during these pit stops, most notably Johnson. Once the green flag pit stops cycled through on lap 64, Jeff Gordon had the lead.
Debris on the racetrack brought out the third caution on lap 86, with Gordon still out in front. Stewart led the race at the restart, and he was still leading at halfway and when the fourth caution came out on lap 105 for debris. On lap 137, there came another round of green-flag pit stops, with Stewart still taking the lead. The fifth caution came out on lap 144, and the sixth one came on lap 150 when Jimmie Johnson spun out again, but tagged Scott Riggs in the right rear, sending him rolling down the backstretch grass, and ending up 20 feet from Lake Lloyd.
Waltrip brought out the seventh caution, allowing him to leave the race and led to another round of pit stops on lap 164. Jason Leffler and Kasey Kahne came together on pit road, dropping them both down the field. The wreck on pit road occurred when Kasey Kahne, who was 4th when the pit stops began, was exiting his pit stall, and Leffler was turning into his, unbeknownst to Kahne. Kahne would later rebound before becoming a victim of a couple of crashes not of his own making.
With 32 laps to go, John Andretti, running three-wide and following a group of cars going four-wide, crashed and turned into Leffler, taking that driver out of the race. This would bring up the eight caution, with Stewart still out in front. Stewart became the first driver since Bobby Allison in 1981 and 1982 to lead the most laps in two consecutive Daytona 500's.
The "Big One" occurred on lap 184. This began when Greg Biffle ran into Scott Wimmer, collecting 11 cars in turn 3. Scott Wimmer's car took the worst of it, as his car went onto the apron, flipped over four times, spun on its nose, and crashed hard on its wheels. This crash brought out the ninth caution. Only some cars chose to pit, and Stewart and the others stayed out. Earnhardt, Jr., who had languished in midfield for the earlier part of the race, was now up to third place. Kasey Kahne was right in the middle of this crash in his #9 mango colored Dodge Charger, but managed to miss it. Kahne charged again back up through the field when the race went back green.
When the race restarted on lap 187, Andretti drove straight into Mike Skinner, starting a chain reaction crash involving at least eight cars, bringing out the immediate 10th caution. This crash was the result of someone (possibly Skinner) missing a gear at the restart. Kasey Kahne was also involved in this crash, because as he checked up Dale Jarrett in the 88 accidentally punted him into the infield grass. Kahne spent a lot of time on pit road, but he did not lose a lap, and apparently his car was, or should have been being checked for fender rubs, when the race restarted Kahne made his way from about the 20th position to about the 8th position, but there was clearly still a tire rub on his right front fender; because it was clearly smoking, and FOX commentator Darrel Waltrip even made mention of it, as he made his way back up through the field again.
The race restarted with six laps to go. With five to go, Earnhardt, Jr. briefly took the lead, but Stewart retook it on the next lap. The two drivers raced side-by-side until Earnhardt, Jr. retook the lead. Gordon took the lead before the 11th caution came out with three laps to go.
The caution came out when Kasey Kahne was on the outside moving forward from the 8th position trying keep his momentum up and move into the top 6 or so, as Kurt Busch made a pass on Tony Stewart, who was in the lead; but Jeff Gordon was also fighting on the outside with Stewart for the lead; Kahne slid up the race track hard probably due to a cut tire and as he did so, his teammate Jeremy Mayfield in the 19 car apparently got into the back of him as well and Kahne went into the wall. He could not get off the wall until about the middle of the backstretch, when NASCAR finally brought out the caution.
Kahne would end up scored 22nd after being crashed while running 7th and possibly moving up into the top 5 to contend for the win. Oddly as the cars came around for the green flag Kahne's teammate Jeremy Mayfield came down to pit road from running 9th on the track, but apparently returned to the race and would end up finishing a position behind his teammate. The race length of 200 laps and 500 miles (800 km) was completed under yellow, so a green-white-checker finish would take place. The race restarted on lap 202 with two laps to go. Despite much activity behind him, Gordon was able to hold off Kurt Busch and Earnhardt, Jr. to win his third Daytona 500 victory.
This was the third-slowest Daytona 500 to go the distance, with only both the 1960 and 2011 races were slower. Two other runnings of this race in the 2000s were also slower, but they both were rain-shortened.