The 2004 NASCAR Nextel Cup Series was the 56th season of NASCAR Nextel Cup Series in the United States and the 33rd modern-era Cup series season. The season began on Saturday, February 7, and ended on Sunday, November 21. Kurt Busch, who drove a Ford for Roush Racing, was the Nextel Cup champion.
This was the first season that NASCAR utilized the Chase for the Nextel Cup format that began with the Sylvania 300 on Sunday, September 19. Under the format rules, the top 10 drivers (and any additional drivers within 400 points of the leader) by the end of the 26th race would be eligible to compete in a final 10-race playoff to determine the NASCAR Nextel Cup champion.