The deal is believed to be worth approximately $100 million, the St. Louis Post Dispatch reported. The Cardinals, while not releasing a figure, said the deal was the largest contract in team history for a pitcher.
"Adam represents everything the Cardinals look for in a player," Cardinals Chairman Bill DeWitt Jr. said in a statement. "He is an elite pitcher with a tremendous work ethic, a great teammate and leader, and a winning, championship caliber player. He has the highest personal qualities and personifies the Cardinals tradition of excellence."
Wainwright, 31, missed the 2011 season due to Tommy John surgery but returned last season with a 14-13 record and 3.94 earned run average in 198 2/3 innings.
He is 80-48 with a 3.15 ERA in 214 games in his career. He was second in the National League Cy Young Award voting after winning 20 games in 2010.