The team announced Friday that the deal will keep the 25-year-old forward in Boston through the 2013-14 season.
A second-round draft pick in 2003, Bergeron has 99 goals and 181 assists in 376 regular-season games, as well as five goals and 15 assists in 31 playoff games.
He had 19 goals and 33 assists last season to tie David Krejci for the team lead with 52 points.
Bergeron, entering his seventh NHL season, missed most of the 2007-08 season because of a severe concussion.
The Bruins, who open their season with two games against the Phoenix Coyotes this weekend in the Czech Republic, did not disclose terms of the deal.