Simoncelli, just 24 years of age, died on lap two of the race after his Honda skidded and veered across the track and straight into the path of Colin Edwards and Valentino Rossi.
Edwards, who also came off his bike due to the collision, suffered a dislocated shoulder.
The race was immediately red-flagged but it appeared as though nothing could save Simoncelli who lay motionless on the track following the crash, his helmet flung from his head. He was taken by ambulance to the circuit's medical center but was announced dead at 16:56 local time.
Doctors said he sustained massive trauma to the head, neck and chest areas.
Tragically, it was at Sepang almost three years ago to the day that Simoncelli, racing for Aprilia, clinched the 2008 250cc World Championship after finishing third in the Malaysian race.
Following the death of Indy 500 winner Dan Wheldon only a week ago, it comes with great sadness that we must say goodbye to another persona from the world of motorsport. At the same time, we’re sure both of them would be happy to know the sports they competed in were here to stay.