The 2009 Sylvania 300 was the twenty-seventh stock car race of the 2009 NASCAR Sprint Cup Series and the first in the ten-race season-ending Chase for the Sprint Cup. It was held on September 20, 2009, at New Hampshire Motor Speedway in Loudon, New Hampshire, before a crowd of 101,000 people. The 300-lap race was won by Mark Martin of the Hendrick Motorsports team after starting from fourteenth position. Denny Hamlin of Joe Gibbs Racing finished second and Earnhardt Ganassi Racing's Juan Pablo Montoya was in third place.

Martin was leading the Drivers' Championship heading into the race because of a redistribution of the points-scoring system that saw him receive an additional forty points for achieving four race victories in the preceding 26 events. Montoya, who initially held the pole position by recording the fastest lap time in qualifying, was immediately passed by Tony Stewart. One lap later, Montoya reclaimed the lead. Chase for the Sprint Cup participants Hamlin and Kurt Busch were in the top ten for most of the race. Martin became the leader of the race, after the leaders made their pit stops. Martin retained the first position to win the race, his fifth of the 2009 season. There were eleven cautions and twenty lead changes among ten different drivers during the race.

The race was Martin's fifth win of the season, as well as the 40th and final win of his Cup career. After the race, Martin maintained his lead in the Drivers' Championship, thirty-five points ahead of Hamlin, who advanced to second, and equal on points with Johnson. Chevrolet maintained its lead in the Manufacturers' Championship, thirty-nine points ahead of Toyota and eighty-one ahead of Dodge, with nine races of the season remaining. The race attracted 5.04 million television viewers.

The 2009 Sylvania 300 was the twenty-seventh of thirty-six scheduled stock car races of the 2009 NASCAR Sprint Cup Series and the first in the ten-race season-ending Chase for the Sprint Cup. It was held on September 20, 2009, in Loudon, New Hampshire, at New Hampshire Motor Speedway, an intermediate track that holds NASCAR races. The standard track at New Hampshire Motor Speedway is a four-turn oval track, 1.058 miles (1.703 km) long. The track's turns are banked at two to seven degrees, while the front stretch, the finish line, and the back stretch are banked at one degree.

Before the race, twelve drivers gained qualification to the Chase for the Sprint Cup; each of them had no fewer than 5,000 points and those who won races over the course of the season received an additional ten points. This was done through a redistribution of the points system. Mark Martin led the Drivers' Championship with 5,040 points by virtue of his four victories in the preceding 26 races, followed by Tony Stewart and Jimmie Johnson who were tied for second place on 5,030 points. Denny Hamlin, was 5,020 points, was tied with Kasey Kahne, with Jeff Gordon, Kurt Busch and Brian Vickers all level with 5,010 points. Carl Edwards, Ryan Newman, Juan Pablo Montoya and Greg Biffle rounded out the top twelve with 5,000 points each. In the Manufacturers' Championship, Chevrolet was leading with 190 points, thirty-six points ahead of their rival Toyota in second. Dodge and Ford were tied on points in the battle for third place. Biffle was the race's defending champion.

Johnson had qualified for all six previous Chase for the Sprint Cups and spoke of his expectations, "I think we've got our best chance for a really exciting Chase. We're really running well. I feel really good at the races in the Chase." Martin commented on his prospects, "I feel like a whole new person — a huge weight is off my shoulders. To make this thing is the icing and now we get to go race for the cake." Montoya was the first non-American driver to advance to the Chase for the Sprint Cup, and said he felt he was under no pressure to be in it, adding, "If I win the Cup, cool. That's it. That's not a big deal for me. I don't get any special treatment or anything. I wouldn't mind getting some but I don't."

Three practice sessions were held before the Sunday race—one on Friday, and two on Saturday. The first session lasted 90 minutes, and the second 45 minutes. The final session lasted 60 minutes. During the first practice session, Montoya was fastest with a lap of 28.749 seconds, placing ahead of Kevin Harvick in second and Clint Bowyer in third. Stewart took fourth position, and Martin placed fifth. Kurt Busch, A. J. Allmendinger, Kyle Busch, Johnson and Hamlin rounded out the top ten fastest drivers in the session.

A total of forty-five drivers were entered in the qualifier on Friday afternoon; due to NASCAR's qualifying procedure, forty-three were allowed to race. Each driver ran two laps, with the starting order determined by the competitor's fastest times. On his second timed lap, Montoya clinched his second pole position of the season and of his career, with a track-record lap of 28.545 seconds. He was joined on the grid's front row by Stewart. Kurt Busch qualified third and Hamlin took fourth after holding pole position for most of the season. Edwards started fifth. David Stremme was the fastest driver who was unable to advance for the Chase for the Sprint Cup in sixth. Martin Truex Jr., Bobby Labonte and Kyle Busch completed the top nine qualifiers. Jeff Gordon, one of the drivers in the Chase for the Sprint Cup, qualified tenth, while Kahne set the eleventh-fastest time. The two drivers who failed to qualify for the race were Derrike Cope and Dexter Bean. After the qualifier Montoya said, "You know how these races go, "If it was a 10-lap shootout, I'll say, 'Hey, we're looking good.' But it's like 200 laps, 300 laps or something, or 400, I don't even know. It's a bunch of laps. As long as I lead the last one I don't care."