Darche, who was scheduled to become an unrestricted free agent on July 1, completed his eighth season in the League in 2010-11.
The 34-year-old forward set personal-highs with 12 goals and 26 points in 59 games. He produced 90 shots and sported a plus-7 rating while averaging 11:16 seconds of ice time per game for coach Jacques Martin. Darche added 1 goal and 2 points in a seven-game series loss to the Boston Bruins in the opening round of the Stanley Cup Playoffs.
"We are very pleased to have reached an agreement with Mathieu Darche," Gauthier said. "Mathieu is a classy veteran player who displays great leadership and determination, and we strongly believe he can help us achieve our goals in the upcoming season."
Since 2000-01, Darche has registered 60 points (25 goals, 35 assists) in 189 NHL regular-season games. Prior to joining the Canadiens, Darche had stints with the Columbus Blue Jackets, Nashville Predators, San Jose Sharks and Tampa Bay Lightning. A native of Montreal, he first signed with the Canadiens as a free agent in July 2009.