De La Rosa's deal is for $5.6 million, and the left-hander could make another $300,000 in performance bonuses. He earned $2 million last year.
Barmes gets $3,225,000, and Buchholz $1,055,000.
De La Rosa was 16-9 with a 4.38 ERA last season, setting a franchise record for lefties with 193 strikeouts. After opening 0-6, he led the majors with 16 wins from June on.
Barmes hit 23 home runs last year for Colorado, a team record for a second baseman. He also had career highs in hits (135), RBIs (76) and runs (69) to help the Rockies make the playoffs as the NL wild card.
Buchholz missed last season following right elbow surgery. He was 6-6 with a 2.17 ERA for the Rockies in 2008.