The 26-year-old current deal was due to expire next summer, but the utility man has agreed on a new two-year deal.
Jansen has recently been linked with a move to Liverpool.
“We are happy to announce the new agreement with Marcell Jansen,” Hamburg sporting director Frank Arnesen told Bild.
“Marcell is now in the position that will enable him to take over a key role in the future of the Hamburger SV first team.”
