Paramedics worked to revive the Belgian, doing CPR for an extended period of time before airlifting him to a nearby hospital. Doctors were unable to revive Weylandt.
"Today, our teammate and friend Wouter Weylandt passed away after a crash on the third stage of the Giro d’Italia," said Leopard-Trek Manager Brian Nygaard. "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."
The third stage continued on, with riders not informed of the grave nature of Weylandt's crash, but race organisers canceled the podium ceremonies for stage winner Angel Vicioso (Androni Giocattoli) and new leader David Millar (Garmin-Cervelo).
Weylandt began his professional career as a trainee with the Quick Step team in 2004, following a victory the U23 Tour of Flanders and podium placings at the U23 Paris-Roubaix and E3 Prijs Harelbeke.
While his first of six full seasons with Quick Step was delayed by a case of glandular fever, his promise in the Classics was demonstrated with a second place in the 2006 Nokere Koerse.
While he spent much of his time at Quick Step as one of Tom Boonen's main helpers, he earned his victory in the top ranks in the 2007 Driedaagse van West-Vlaanderen, where he also took second overall. He followed that with the Ronde van het Groene Hart and stages of the Tour of Belgium and Ster Elektrotoer.
After taking his first Classics podium with a third in Gent-Wevelgem, Weylandt won the 17th stage of the 2008 Vuelta a España in his first Grand Tour appearance. He last year won the third stage of the Giro d'Italia, where he bested the top sprinters in the peloton after a marathon stage to Middelburg.
Weylandt signed with the nascent Leopard Trek squad for the 2011 season.
Cyclingnews extends our deepest sympathies to Weylandt's family, friends and teammates.
More as information comes available