The Brazil international will wear the iconic jersey at Stamford Bridge for the 2012-13 season following the Ivorian's departure to Shanghai Shenhua
The Brazil international, who is on Olympics duty with his country at London 2012, will take over from the Ivorian whose exploits as the club's former No.11 saw him become a legend at Stamford Bridge before leaving, after having clinched the Champions League, in the summer.
Oscar joined Roberto Di Matteo's side from Internacional last month for a fee believed to be in the region of £25 million and will battle with likes of fellow new signing Eden Hazard, Juan Mata, Florent Malouda and Daniel Sturridge for a place in the Blues' starting XI.
The 20-year-old follows in the footsteps of the likes of Damien Duff and Boudewijn Zenden, who both wore the No.11 shirt prior to Drogba taking over in 2006.
Dennis Wise is another club legend to have had the No.11 on his back, having taken the shirt back in 1993 when squad numbers were first introduced in English football.