In the National Football League (NFL), the lowest official passer rating that a quarterback (QB) can achieve is 0.0. To achieve a passer rating of 0.0, a QB must have no touchdowns, complete no more than 30% of his pass attempts, average less than 3 yards per attempt and throw an interception on at least 9.5% of attempts. The NFL does not, however, count such games by QBs who attempt fewer than 10 passes in a game.
Terry Bradshaw posted a zero rating on a record three occasions, while seven other QBs have two games of 0.0. Gary Keithley is the only QB ever to post zero ratings two straight weeks (1973). There have been two occasions where a starting QB, and his mid-game replacement, have both earned a zero rating in the same game: starter Joe Namath and replacement Richard Todd with the New York Jets (1976), and starter Terry Bradshaw and replacement Cliff Stoudt with the Pittsburgh Steelers (1982). Only once have opposing QBs both posted a zero rating: Gary Keithley and the St. Louis Cardinals defeated Bob Lee and the Atlanta Falcons (1973). No starting QB with a passer rating that low has won the game since Norm Snead in 1976.
Eleven QBs have had a zero passer rating and also earned a perfect (158.3) passer rating during their careers: Johnny Unitas, Joe Namath, Terry Bradshaw, Len Dawson, Bob Griese, James Harris, Bob Lee, Dan Fouts, Craig Morton, Eli Manning, and Peyton Manning.