The decision to exercise the options was expected.
The NFL's new collective bargaining agreement makes fifth-year options fully guaranteed. The Browns lock in Mayfield's $18.8 million and Ward's $13.2 million for the 2022 season.
"Both of those players have really done a nice job for us over the first three years," Browns general manager Andrew Berry said, according to team staff writer Andrew Gribble. "We view both of those guys as young players who continue to ascend."
Cleveland's move comes ahead of the May 3 deadline to exercise fifth-year options.
Mayfield led the Browns to their first playoff victory in 26 years. The No. 1 overall pick in the 2018 draft turned in one of his most efficient campaigns, throwing for 3,563 yards, 28 touchdowns, and eight interceptions while completing 62 % of his passes.
Ward has provided Cleveland with stability in the secondary. The 23-year-old was named to a Pro Bowl as a rookie, tallying 53 tackles, three interceptions, and 11 passes defended in 2018. The Ohio State product has accumulated seven interceptions, 40 passes defended, and 143 tackles through three campaigns.
Both Mayfield and Ward are now eligible to receive multi-year extensions. Mayfield could be the first among the class of 2018 quarterbacks - which includes the Buffalo Bills' Josh Allen and Baltimore Ravens' Lamar Jackson - to sign an extension.