The 2005 Sylvania 300 was the twenty-seventh stock car race of the 2005 NASCAR Nextel Cup Series and the first in the ten-race season-ending Chase for the Nextel Cup. It was held on September 18, 2005 at New Hampshire Motor Speedway in Loudon, New Hampshire. The 300-lap race was won by Ryan Newman of the Penske-Jasper Racing team. Tony Stewart finished second and Matt Kenseth came in third.