The Nerazzurri have communicated they have secured the services of the experienced striker on a permanent deal with reports suggesting the 35-year-old will be there till June
The Nerazzurri were keen to add some more depth to their attack this winter, and head coach Andrea Stramaccioni has now gotten the reinforcements he was after.
Rocchi had made well over 200 Serie A appearances for Lazio since joining the club from Empoli in the summer of 2004, but had lost his starting berth in recent years.
Therefore, the 35-year-old was eager to move on, and he will now be looking to get his career back on track at Inter.
The veteran attacker started his professional career at Juventus, but failed to break into the first team at the Turin giants. He also played for clubs such as Pro Patria, Fermana, Saronno, Como and Treviso over the years.