Redding, an eight-year veteran listed at 6-foot-4 and 292 pounds, had 20 tackles last season for the Seahawks, including two sacks. ESPN NFL Insider Adam Schefter first reported the signing.
Redding's deal is worth $6 million over the two years, a league source told Schefter.
Redding has 221 career tackles, including 18 sacks, in 101 games with the Seahawks and Detroit Lions. He played the 2009 season in Seattle after spending his first six seasons in Detroit.
"Cory is a guy who plays like a Raven," general manager Ozzie Newsome said. "He hustles, he plays with intelligence, and he can play multiple positions like many of our defensive players. He's been a starter at both inside tackle and defensive end. And I am sure our coaches will use him in both positions."
Redding was an unrestricted free agent. His best season came in 2006, when he had 16 starts and finished with eight sacks and 70 tackles.
"We're excited about Cory. He fits us," Ravens coach John Harbaugh said. "I think in our defense he'll have a chance to really blossom."
Harbaugh expects to use Redding in a variety of ways.
"He can rush from the inside, rush from the outside, he can probably even play the rush position which is where we put Dwan Edwards at times on first down last year," Harbaugh said. "I think he's a similar player to Dwan. Obviously, Dwan had a great year for us. We're hoping he fills that spot for us."
He was drafted by Detroit in the third round in 2003 out of Texas.
Information from The Associated Press was used in this report.