Beckett, who led the team with 17 wins last season, said Boston's Fenway Park, Major League Baseball's oldest stadium, was a special place to play and felt the Boston organization helped make players' jobs as easy as possible.
"The people I've talked to, there aren't a whole lot of other organizations out there that do that," Beckett, a twice All-Star, told a news conference at Fenway Park.
"Work in between starts, roundtable things, I could go on here but they make for a very ideal situation for a baseball player. It's really a good place to play."
The deal will keep Beckett with the Red Sox through the 2014 season. Terms of the contract were not disclosed.
The 29-year-old, who was named MVP of the 2003 World Series when he played for the Florida Marlins, has been with the Red Sox since November 2005. He is 65-34 in 123 starts with Boston since the start of the 2006 season.
Beckett, drafted by the Marlins with the second pick in the first round on the 1999 draft, has posted a 106-68 record, 3.81 ERA, 1,331 strikeouts and 429 walks in his 229 Major League appearances.
(Writing by Frank Pingue in Toronto; Editing by Sonia Oxley)