The Bears terminated the veteran's contract, one of several moves they made before Friday's deadline to trim their roster to 53 players.
Receiver Rashied Davis was also among the five players whose contracts were terminated Friday, while 16 were waived, including running back Armando Allen.
Defensive tackle Nate Collins was placed on the reserved/suspended list after the NFL suspended him in July for the season opener against Indianapolis for violating the substance abuse program.
The Bears also traded fullback Tyler Clutts to Houston for cornerback Sherrick McManis on Friday.
McCown was coaching quarterbacks at a North Carolina high school and hadn't taken an NFL snap since 2009 when the Bears signed him last November. Chicago was looking for help because Caleb Hanie struggled after Jay Cutler broke his right thumb, and the veteran wound up appearing in three games and starting two.
He completed 63.6 percent of his passes and earned another shot with the Bears, agreeing to a one-year deal. But with Cutler entrenched as the starter and newcomer Jason Campbell locked in as the No. 2 quarterback, Chicago decided to cut McCown.
Clutts signed just before last year's opener and appeared in all 16 games, but new offensive coordinator Mike Tice prefers to use tight ends. So it was not shocking that the Bears let him go.
McManis appeared in 23 games over two seasons with Houston after being drafted out of Northwestern in the fifth round in 2010 and had one interception to go with 16 special teams tackles and 11 kickoff returns for 230 yards.
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