The 33-year-old, who was previously accused of throwing a water bottle into the Saints crowd in anger, has agreed a deal that will keep him at the club until 2015.
"I am very pleased and I'm proud to be a part of a big prospect," Boruc told the club's official website. "As a club, I believe we can achieve a lot over the next two years, and I'm looking forward to that.
"As I've said before, [the Premier League] is probably the best place to play football and nothing has changed my mind on that since I came to Southampton.
"The new manager has changed a lot. We're playing totally different football, and I think that football is quite nice to watch and quite effective. Playing this style of football you can achieve a lot, and you need to be ambitious in your life."
Boruc moved to the club from Fiorentina last year.