1960–69: The AFL days

The teams first met in 1960 when the Chiefs were known as the Dallas Texans. The Texans beat the Bills 45–28, the teams first game at Buffalo,^[7] then the Texans beat the Bills 24–7.

The two teams met for their first playoff match in the 1966 AFL Championship Game on January 1, 1967. This game was notable where the game would determine the AFL's representative in the first Super Bowl. Kansas City would defeat Buffalo, 31–7, allowing the Chiefs to face the Green Bay Packers.^[8]

The teams would face each other 19 times before the AFL–NFL merger. The teams would have a tied record of 9–9–1 in the AFL with the only tie in the rivalry occurring on September 22, 1963, with the score tied 27–27.^[9]

1971–1986: Post-merger and decline

The two teams first met as members of the newly-formed American Football Conference of the National Football League in the 1971 season, when the Chiefs defeated the Bills, 22–9, at Kansas City's Municipal Stadium. This would be the final regular season game at the stadium, as the Chiefs would move into their current home of Arrowhead Stadium in 1972.

Both teams would struggle to reach the postseason during this time as the Chiefs would endure a 14-year playoff drought from 1972 until 1985. As for the Bills, they would only qualify for the playoffs three times over the same stretch.

Overall, the Bills won most of the games in the 1970s and 1980s, going 6–3 between 1971 and 1986.

1991–2000: Resurgence of the rivalry

In 1991, both teams met in the regular season at Arrowhead Stadium where the Chiefs would defeat the then-defending AFC champion Bills by a score of 33–6. Chiefs running back Christian Okoye ran for 122 yards and rushed for 2 touchdowns on the ground. The Bills were limited to only 211 net yards in the game, and had lost five fumbles.^[10]

The teams would meet again in the 1991 AFC Divisional Round at Rich Stadium, where the Bills would get their revenge on Kansas City. Buffalo led 17–0 at halftime on route to a 37–14 victory. Bills quarterback Jim Kelly would throw for 373 yards passing with 3 touchdowns, while running back Thurman Thomas rushed for 100 yards on 22 carries. With the win, the Bills would advance to the AFC Championship Game for the second straight season, where they would defeat the Denver Broncos by a score of 10–7, allowing the Bills to reach the Super Bowl for the second straight year.^[11]

Prior to the 1993 season, the Chiefs acquired quarterback Joe Montana from the San Francisco 49ers and also signed running back Marcus Allen, both former Super Bowl MVPs. The result of these transactions generated Kansas City as a potential Super Bowl favorite, as well as for the potential to challenge the Bills for supremacy in the American Football Conference.^[12]

The Bills and Chiefs would meet in the regular season in 1993, where Kansas City would defeat Buffalo, 23–7. Despite the Bills jumping out to an early 7–0 lead in the first quarter, Jim Kelly would throw three interceptions, with turnovers effectively costing the Bills the game. Joe Montana would return to the Chiefs' lineup after a missing a month due to an injury. He would throw for two passing touchdowns in the victory.^[13]

The two teams would meet again in that year's AFC Championship Game where the Bills won their fourth straight AFC Championship by a score of 30–13. Montana would suffer a concussion on a three-way sack from Bruce Smith, Phil Hansen, and Jeff Wright, early in the third quarter, which forced Chiefs backup quarterback Dave Krieg into the game. Bills running back Thurman Thomas rushed for 186 yards and added three touchdowns.^[14]

2002–2017: Bills' playoff drought

The Chiefs hosting the Bills in 2009. Quarterback Matt Cassel would play for both teams in his career.

The rivalry would begin to slow down in the 2000s as the Bills would enter what would be a 17 year playoff drought, while Kansas City would remain competitive but would not get past the Divisional Round of the playoffs during this time period. Nonetheless, the rivalry gained notoriety as the teams played each other nine out of ten years from 2008 to 2017.^[15]

The two teams had some notable moments during this time. One such game was the matchup in 2008, when the 54–31 Buffalo victory featured the most combined points between the two teams in the series. Buffalo quarterback Trent Edwards threw for 273 yards with four total touchdowns in the game. For the Chiefs, this game would mark the most allowed points in a single game in franchise history, a record that would be tied in a 2018 game against the Los Angeles Rams.^[16]

The 2010 contest between the Bills and Chiefs used all 75 minutes of the game under the league's then-overtime rules. Buffalo tied the game at 10 late in the fourth quarter thanks to a Ryan Fitzpatrick touchdown pass to Stevie Johnson. The game would go to overtime, where both teams would punt on their first possessions, and then both teams would miss potential game winning field goals on their second possessions of overtime, keeping the game going. After the Bills would punt again, the Chiefs would drive down the field, where Ryan Succop would kick the game-winning field goal from 35 yards as the clock expired on the overtime period.^[17]

The Bills and Chiefs would meet for a total of 12 times between 2002 and 2017, with each team winning six games each.

2020–present: Josh Allen vs. Patrick Mahomes

Josh Allen (top) and Patrick Mahomes (bottom) have been key figures in the rivalry in recent years.

All of the games in the current decade have featured the prominent quarterback play of Bills quarterback Josh Allen and Chiefs quarterback Patrick Mahomes, who have become key figures in the long-standing rivalry.^[18] Both quarterbacks have been noted for their physicality, strong arm strength, and mobile styles of play, where they have demonstrated to escape running with the football while under pressure as well as effectively scramble when called upon.^[19][20][21]

The 2020 season marked the first time where Bills quarterback Josh Allen and Chiefs quarterback Patrick Mahomes met in the regular season. The Chiefs would defeat the Bills, 26–17 in Buffalo. In the game, Mahomes passed for 225 yards and threw for two touchdown passes, both of which were caught by tight end Travis Kelce, while running back Clyde Edwards-Helaire rushed for 161 yards on the ground.^[22] Both teams would meet again in the postseason in the AFC Championship Game at Arrowhead Stadium. Buffalo would take an early 9–0 lead, but the lead would not last, as Kansas City took control of the game in the second quarter, and cruised to a 38–24 victory to repeat as conference champions, allowing them to advance to Super Bowl LV.^[23]

Both teams met in the 2021 regular season, where the Bills would defeat Kansas City, 38–20. Josh Allen threw for 315 yards with three passing touchdowns while adding 59 yards on the ground and a rushing touchdown. Mahomes threw two interceptions in the contest, with one of those returned for a touchdown by Bills safety Micah Hyde.^[24]

The two teams met in the 2021 AFC Divisional Round of the playoffs, where the game would be noted for its dramatic conclusion. The game featured four lead changes and 25 points scored n the final two minutes of regulation. Allen would throw for 329 yards and four touchdown passes for Buffalo, while Mahomes threw for 378 yards and added three touchdown passes for Kansas City. With 13 seconds remaining, Allen threw a touchdown pass to wide receiver Gabe Davis to give the Bills a 36–33 lead. However, Mahomes would lead a 44-yard drive with the little time remaining, resulting in a 49-yard field goal by Chiefs kicker Harrison Butker to tie the game and send it to overtime. Kansas City would win the overtime coin toss, where they would quickly score a touchdown to give the Chiefs the 42–36 win.^[25]

The game received praise from commentators for both teams' performances,^[26][27][28] while also scrutinizing the league's overtime rules.^[29] As a result of this game and other similar games in past seasons, the NFL changed the overtime rules for postseason games beginning with the 2022–23 postseason, to allow both teams at least one possession of the football in overtime.^[30]

The 2022 game between the two teams was another tight back-and-forth contest as both teams competed closely until the fourth quarter. Kansas City took a 20–17 lead on a field goal with under 10 minutes to play, then the Bills defense forced a three-and-out on the Chiefs next possession. On the ensuing drive, Josh Allen and the Bills offense marched down the field, where Allen would throw a go-ahead touchdown pass to tight end Dawson Knox with 1:04 left in the quarter. On the Chiefs' final possession of the game, Patrick Mahomes was intercepted by Bills cornerback Taron Johnson, preserving a 24–20 victory for Buffalo.^[31]

The teams met for the fourth straight season in 2023. Buffalo got out to a hot start, jumping out to a 14–0 lead. However, Kansas City would tie the game at 17 in the fourth quarter. With under 2 minutes left to play, the Bills re-took the lead on a 39 yard field goal by Tyler Bass. On the Chiefs' ensuing possession, Kansas City appeared to take the lead on a hook and lateral touchdown, as tight end Travis Kelce caught a pass, where he then threw a lateral to wide receiver Kadarius Toney, who ran into the end zone. However, Toney was ruled offsides on the play, negating the score. After the penalty on the 2nd down play, Mahomes threw two incomplete passes, turning the ball over on downs, securing the Bills victory.^[32]