The new two-year deal will keep Slomka at Hannover until the summer of 2013.
He said: “I’m staying with Hannover out of a deep conviction.
“I’m enjoying working here, getting a lot of support and the team has developed fantastically. I want to build on that, which is especially appealing in my home town.”
Hannover president Martin Kind said: “Together with the team, he has achieved a lot in the past year. He avoided relegation and has followed that with the best first half to a season in the club’s history.”