CBS drew 30.8 million viewers for Sunday’s Chiefs-Bills game, the network’s fifth-most-watched regular-season Sunday NFL broadcast since returning to the league in 1998 and the most-watched Week 9 game on CBS since the undefeated Colts-Patriots clash in 2007.
The game—delivered to 100% of U.S. markets—peaked at 35.2 million viewers during the fourth quarter, when Josh Allen’s 26-yard scramble on 4th-and-2 sealed Buffalo’s 28-21 win.
Earlier, CBS’s 1 p.m. ET regional window, led by Colts-Steelers in 68% of markets, averaged 18.6 million viewers—its strongest Week 9 early window since 1998.
The audience made Chiefs-Bills the most-watched program of the week across all networks, surpassing Fox’s World Series Game 7. It ranks as the second-highest-rated game of the 2025 NFL season, behind only the Chiefs-Eagles Super Bowl rematch.
CBS is averaging 19.4 million viewers per game this season, up 6% year-over-year and the network’s best mark since reclaiming NFL rights. The NFL’s growing use of national flex windows is fueling record viewership, with Chiefs-Bills underscoring the drawing power of the Mahomes-Allen rivalry.