The organisers cancelled Sunday's race as soon as the extent of Simoncelli's injuries became apparent.
A statement on the MotoGP official website read: 'On Sunday 23rd October, during the MotoGP race at the Shell Advance Malaysian Motorcycle Grand Prix at the Sepang International Circuit, San Carlo Honda Gresini's Italian rider Marco Simoncelli suffered a serious accident in which he received critical injuries.
Moment of horror: Simoncelli loses control on the second lap
Collision: Simoncelli fatally falls off of his Honda after colliding into Colin Edwards
Fall: Edwards spins off the track along with Simoncelli's bike as the 24-year-old Italian devastatingly lies motionless
'The race was stopped immediately with the red flag and Simoncelli was transported by ambulance to the circuit medical centre where the medical staff worked to resuscitate him.
'Despite their efforts, Marco sadly succumbed to his injuries at 4:56pm local time.
Sorrow: Honda team members (above and below) react to the sad news
'Everybody involved in MotoGP extends its deepest condolences to Marco's family, friends and team at this tragic loss.'
Losing control: Simoncelli (No 58) crashed on the second lap of the race, riding between Edwards and Valentino Rossi
Emergency: Race marshalls quickly arrive at the scene to assist the stricken Simoncelli
Simoncelli, who won the 250cc world championship in 2008, clinching the crown in Sepang, stepped up to MotoGP in 2010.
His death was the first fatality in MotoGP since Japan's Daijiro Katoh died from his injuries sustained at the 2003 Japanese Grand Prix.
Wheeled away: Track officials remove Simoncelli's motorcycle after the dreadful accident
Newly-crowned champion Casey Stoner admitted immediately after the crash he had feared for Simoncelli.
'As soon as I saw the footage it just makes you sick inside,' the Australian told BBC2.
Cancelled: Rubbish covers the track after the race was abandoned early in Sepang
