The Xfinity 500 is a NASCAR Cup Series stock car race held at Martinsville Speedway in Ridgeway, Virginia. The race is traditionally held in the fall and has been run in every NASCAR Cup Series season, starting with the sixth event in the inaugural 1949 season, making it the oldest NASCAR race on the schedule. It is currently the ninth race of ten in the Cup Series playoffs, and the final race of the Round of 8.^[2] Since 2015, NBC has held the broadcast rights for the final 20 races of the season, including this race. Ryan Blaney is the defending winner of the event.

Prior to lights being installed, the race started at 1:30 p.m. Eastern, generally the earliest start time among the playoff races on the schedule, in an attempt to finish the race before darkness. Following a series of incidents involving both the October Late Model race and the NASCAR Cup races in the 2010s, most notably both fall 2015 races that ended in near-darkness, the track added lights for the 2017 season. The NASCAR Cup Series fall race now finishes at night, and the Late Model race is held at night. The Tums sponsorship returned in 2008, as their Goody's Powder brand sponsored the race from 1983 to 1995 and returned as a sponsor for the spring race in 2007. Tums and Goody's sponsored the fall race through 2016. As per Martinsville tradition, the winner of this race receives a custom-built grandfather clock.^[3]

• 1954 & 1958: Race shortened due to darkness.
• 1967–1970: Richard Petty went on to win 4 consecutive Martinsville Fall Races in this time frame. He would become the f1st of only 2 drivers in the track's history, and the only driver in the history of the Fall Race, to win the same Martinsville event 4 years in a row. Rusty Wallace would accomplish this feat in the spring race from 1993–1996.
• 1973 & 1976: Race shortened due to rain.
• 2001: Race postponed from Sunday to Monday due to rain.^[79]
• 2007–2009, 2015, 2017, and 2021: Race extended due to NASCAR overtime.