The Olympic Park Legacy Company (OPLC) made a unanimous recommendation to back West Ham's plans over an audacious bid from Tottenham, who planned to remove the running track and knock down the 500 million pound stadium in favour of a purpose-built soccer ground on the site.
The authorities are keen to have a viable tenant to ensure that the stadium, centrepiece of the 9.3 billion pound Olympics, helps to regenerate the rundown area of east London, one of the poorest parts of the capital.
"We are confident that this represents the very best legacy for the Stadium," she said.
"The IOC welcomes the Olympic Park Legacy Company's decision which allows Games preparations to continue and paves the way for a great sporting legacy," the IOC said in a brief statement.
"I have always said that Britain, whose history and legendary athletes have been an inspirational example, deserves a world class athletics venue. Now athletics can continue to thrive in the Olympic Park, long after the Olympic flame has gone out."
Karren Brady, vice chairman of West Ham, said: "We have been granted a once in a lifetime opportunity to grow our club. The nation has kept its promise and we will keep ours."
Tottenham, backed by American entertainment giant AEG, argued that West Ham's plan to incorporate an athletics track inside a soccer stadium would be unsustainable.
"I wouldn't want to watch football sitting miles away from the pitch in a stadium that holds 60,000 people that is half full. That wouldn't appeal to me at all," he said.
"It is probably the only time in my life I have or will celebrate a victory for West Ham," Tim Framp, a spokesman for the 'We are N17' group, told Reuter
