The Cubs avoided arbitration with all three. Farnsworth got a raise from $1.4 million to $1,975,000. Patterson, who made $480,000 last season, received an increase to $2.8 million.
Barrett, who made $1.55 million last season, had asked for $3.9 million in arbitration while the Cubs offered $3 million before the multiyear deal was reached.
Barrett batted 287 with a career-high 16 homers and 65 RBI in 130 games, including 19 starts.
Chicago obtained Barrett in a trade with Oakland on Dec. 16, 2003 one day after Oakland acquired him from Montreal. Prior to the trades, he had spent his entire six-year career with Montreal. He has a .260 batting average with 54 homers in 676 major league games.
Farnsworth, whose fastball has been clocked at 100 mph, appeared in 72 games last season with a 4-5 record and 4.73 ERA as a setup and situational reliever.
Patterson, 25, batted .266 last season with career highs in doubles (33), homers (24), RBI (72) and stolen bases (32) in his first full season after tearing the anterior cruciate ligament in his left knee.
The third overall pick in the 1998 June draft, Patterson broke into the majors in 2000. He has batted .262 with 57 homers, 197 RBI and 71 stolen bases in 463 games.
The Cubs also agreed to a minor league deal with right-handed reliever Scott Williamson.
Williamson, who underwent elbow surgery in mid-October, will be invited to the major league camp in spring training.
He was 0-1 with a 1.26 ERA in 28 relief appearances for Boston last season. In a seven-year career, Williamson is 25-24 with 55 saves with a 2.98 ERA in 269 appearances. He was chosen NL Rookie of the Year with the Reds in 1999 when he went 12-7 with 19 saves and a 2.41 ERA in 62 relief appearances.