The 2006 Subway 500 was the 32nd stock car race of the 2006 NASCAR Nextel Cup Series and the sixth in the ten-race Chase for the Nextel Cup. It was held on October 22, 2006, before a crowd of 65,000, at Martinsville Speedway in Ridgeway, Virginia, United States. Hendrick Motorsports driver Jimmie Johnson won the 500‑lap race starting from the ninth position; Denny Hamlin of Joe Gibbs Racing finished second, and Bobby Labonte of Petty Enterprises was third.

Jeff Burton was the driver who led the Drivers' Championship going into the race with a 45-point margin over Matt Kenseth in second. Kurt Busch won the pole position with the fastest lap time in qualifying. He was immediately passed by Jeff Gordon at the start of the race. Gordon held the lead for 143 laps, until Johnson took the lead for one lap. Gordon regained the lead on the next lap, only to lose it to Johnson again on the 153rd lap. Labonte moved into the lead on lap 406 and held it with 55 laps remaining when he was passed by Johnson. At the race's final restart on lap 495, Hamlin challenged Johnson for the lead, but the latter held off Hamlin's passing maneuver and won the race. There were 18 cautions and 16 lead changes by five different drivers during the race.

It was Johnson's fifth win of the 2006 season and the 23rd of his career. The result advanced him from to third in the Drivers' Championship, 41 points behind Kenseth (who took over the championship lead when Burton retired during the race; this caused Burton to fall to fifth in the championship, one point behind Hamlin). Chevrolet maintained its lead in the Manufacturers' Championship, 53 points ahead of Dodge, and 61 ahead of Ford with four races left in the season.

The Subway 500 was the 32nd of 36 scheduled stock car races of the 2006 NASCAR Nextel Cup Series and the sixth in the ten-race season-ending Chase for the Nextel Cup. On October 22, 2006, it was held at Martinsville Speedway in Ridgeway, Virginia, a short track that holds NASCAR races, and ran for a total of 500 laps over a distance of 263 mi (423 km). The standard track at Martinsville Speedway is a four-turn, paperclip-shaped 0.526-mile (0.847 km) oval. Its turns are banked at eleven degrees, and neither the front stretch (the location of the finish line) nor the backstretch is banked.

Before the race, Jeff Burton led the Drivers' Championship with 5,763 points, with Matt Kenseth second on 5,718 points and Kevin Harvick with 5,674 points in third. Mark Martin and Dale Earnhardt Jr. were fourth and fifth, and Denny Hamlin, Jimmie Johnson, Kasey Kahne, Kyle Busch and Jeff Gordon rounded out the top ten drivers competing for the 2006 Chase for the Nextel Cup. In the Manufacturers' Championship, Chevrolet led with 237 points; Dodge was second with 179, followed by Ford with 173. Gordon was the race's defending champion.

After falling from seventh to tenth in the Drivers' Championship at the previous race (at Charlotte Motor Speedway), Gordon said he would try and win races to return to contention for the championship. Jeff Burton called the Subway 500 "another volatile race in the Chase" and thought it would significantly impact the chase contenders. Although Kenseth felt the race would be the toughest for his team, he believed a good finish would put him in a better position for the championship because of his good results at the tracks following the Martinsville race. After a good finish at Charlotte, Earnhardt felt he was in "good shape": "Jeff has been at this a long time, but I don't look at him as indestructible. If he has a mistake or even a couple of bad runs, it will completely shake up the points." After winning the Busch Series championship, Harvick focused on the Nextel Cup championship: "We're excited about it, proud of what we've done this year, and, hopefully, we can do what we need to do on the Cup side in the next five weeks. I have never had a season like this." Hamlin thought he would perform well at Martinsville, where he felt comfortable. He and his team did not rule themselves out of contention for the title.

In preparation for the race, NASCAR held the last of its test days for Nextel Cup entrants on October 16–18 at Homestead-Miami Speedway. Sessions began at 1:00 p.m. Eastern Daylight Time (EDT), paused from 5:00 to 6:00 p.m., and concluded at 9:00 p.m. Fifty-eight cars, a mix of Cars of Tomorrow and 2006 cars, participated in the October 16 afternoon session. Reed Sorenson was quickest with a speed of 171.652 miles per hour (276.247 km/h), and Casey Mears had the highest speed of 173.077 miles per hour (278.540 km/h) in the evening session. During the third session (with 75 cars), Kyle Busch had the fastest speed of 175.382 miles per hour (282.250 km/h); Gordon had the highest speed of the three days, at 175.553 miles per hour (282.525 km/h) in the fourth session. During the fifth session, on the afternoon of October 18, 23 cars were tested. Scott Wimmer had the highest speed of 172.364 miles per hour (277.393 km/h), and Jeff Green had the highest speed of 174.639 miles per hour (281.054 km/h) in the evening session.

There were 50 cars represented by 3 different manufacturers entered for the race from a total of 29 teams. One team substituted for its regular driver. Morgan-McClure Motorsports driver Todd Bodine decided to concentrate on the Craftsman Truck Series title and was replaced by Ward Burton, the 2002 Daytona 500 champion. Burton, who had not raced since 2004, went to Motor Mile Speedway to reacquaint himself with NASCAR. According to crew chief Chris Carrier, Burton expressed a large amount of interest in driving at Martinsville: "He's a Virginia driver and we're a Virginia team. That makes for a great combination at Martinsville." On October 18, Roush Racing announced that Craftsman Truck Series driver David Ragan would drive the No. 06 car in four of the season's five remaining races beginning with the Subway 500. Ragan said the experience would help him prepare for his full-time début in 2007.