The 24-year-old has signed a contract that will keep him at Hannover until the summer of 2014.
The Senegal international joins Hannover for an undisclosed fee.
Hannover coach Mirko Slomka said: “I am happy that with Mame Diouf we have another alternative up front.
“We need to bring him in fast so he can help us in the Bundesliga and the Europa League.”
