"Drew and Bo are both very talented quarterbacks who have enjoyed great success as members of the Stampeders," Calgary coach/GM John Hufnagel said in a statement. "They work extremely well together and their decision to sign extensions with the Stampeders gives us great long-term stability at what is obviously a key position."
Tate has been with Calgary since '09. He became the starter late in the '11 season but injuries have limited him to eight regular-season and two playoff starts since then. Tate, 29, has completed 259-of-381 passes for 3,270 yards and 24 TDs with just nine interceptions.
Mitchell, 23, has been with Calgary the past two seasons but was 3-0 as a starter last year. He completed 94-of-135 passes for 1,156 yards with 10 TDs and three interceptions.