Belgian rider Wouter Weylandt was pronounced dead after a horrific crash on the third stage of the Giro d'Italia.
Weylandt, 26, was left bloodied and unconscious and requiring a cardiac massage after a crash which occurred on the descent of the Passo del Bocco around 25km from the finish line.
"Today, our team mate and friend Wouter Weylandt passed away after a crash on the 3rd stage of the Giro d’Italia," said Leopard Trek General Manager Brian Nygaard in a released statement.
"The team is left in a state of shock and sadness and we send all our thoughts and deepest condolences to the family and friends of Wouter.
"This is a difficult day for cycling and for our team, and we should all seek support and strength in the people close to us."
Race officials later claimed his left pedal got stuck in a wall at the side of the road, forcing Weylandt to tumble around 20 metres to the ground below.
He received emergency medical treatment by race doctors and was scheduled to be airlifted to hospital but had to wait as an emergency helicopter looked for a suitable landing spot.
"His heart has stopped beating," announced Auro Bulbarelli, the head of sport for RAI television who first broke the tragic news.
Weylandt, who spent the bulk of his career with the Belgian team Quick Step after turning professional in 2006, won the third stage of the race last year, in Middelburg (Netherlands).
He joined new Luxembourg outfit Leopard-Trek, the home of Australian Stuart O'Grady and the Schleck brothers Andy and Frank, at the start of the season.
Weylandt is the first rider to die in a crash while racing since Kazakhstan's Andrei Kivilev succumbed to head injuries the morning after a crash on the second stage of the 2003 Paris-Nice.
Kivilev's death, while the rider was travelling at a seemingly innocuous speed, signalled the introduction of the mandatory wearing of helmets in the professional peloton.
Weylandt, who hailed from Ghent, is the first fatality on the Giro since 1986 when Emilio Ravasio crashed on the first stage and fell into a coma to die several days later.
Although life and career-threatening crashes are a regular occurrence in cycling, the last fatality on the world's biggest race, the Tour de France, was over a decade ago.
On the race's 15th stage in 1995 Italy's Fabio Casartelli -- a member of Lance Armstrong's Motorola team -- died a few hours after sustaining injuries in a crash on the descent of the Portet d'Aspet in the Pyrenees.
Following the tragedy race organisers cancelled the post-race ceremony in Rapallo, where Spaniard Angel Vicioso, of the Androni team, won the stage ahead of new race leader David Millar of Britain (Garmin).
Factfile on Wouter Weylandt:
Date of birth: September 27, 1984
Place of birth: Ghent, Belgium
Died: May 9, 2011
Teams: Quick Step (2006 - 2010), Leopard (2011)
One-day wins: Nokere Koerse 2007, Circuit des bords de l'Escaut flamand 2008, GP Samyn 2009.
Stage races: Two stages in Three Days of West Flanders (1 in 2007, 1 in 2009), one stage in Tour of Belgium 2007, 1 stage in Ster Elektrotoer 2007, 1 stage in Tour of Benelux 2007, 1 stage in Circuit Franco-Belge 2010
Grands Tours: Tour of Spain: 1 stage in 2008, Giro d'Italia: 1 stage in 2010