A 29-year-old man collapsed and died yesterday while taking part in the Great North Run.
In a brief statement, race organisers Nova International revealed "the tragic loss of life of a 29-year-old male runner at the BUPA Great North Run today and offer our deepest sympathy and condolences to his family and friends".
The company said it was not releasing his name at the request of next of kin.
Following the four deaths that marred last year's half-marathon, organisers introduced extra safety measures for yesterday's event through Newcastle, Gateshead and South Shield.
The organisers said it was unable to give any details of the victim or when during the race he died.
A Nova International spokesman added: "We need to establish the correct information."
A Northumbria Police spokesman said all inquiries regarding the tragedy and the race had to be directed to Nova International.
More than 38,000 people, including celebrities from the world of sport and showbiz, took part in the 13-mile run through Tyneside.
Hendrick Ramaala, from South Africa, won the men's race for the third time in five attempts. Dejene Berhanu, from Ethiopia, took second and American debutant Dathan Ritzenhein third.
The women's race was won by Berhane Adere, ahead of former winner Benita Johnson of Australia and Kenya's Susan Chepkemei.