Gastaldello has signed a three-year extension that will keep him at the club until 2014.
“I am having excellent seasons here, and the club’s faith in me says plenty,” he told the club’s official website.
“I have extended until 2014 and I am super happy. I am in my third season here and I never had any doubts about renewing my contract.”
Gastaldello joined Sampdoria from Juventus in 2007.