The Anthony Nolan Trust is one of two organisations chosen as an official charity for next year's Flora London Marathon.
The trust hopes to raise more than £1.1m to save the lives of those with leukaemia.
Being chosen as an official charity means it is entitled to more Golden Bond runners than non-official charities. The Golden Bond scheme has caused controversy in the past because it leaves many charities unable to get runners (Third Sector, 6 April).
The trust had 180 runners last year - 130 of whom ran through the Golden Bonds bought by the trust.
This year, it expects to have about 220 runners through the bond system and up to 335 through the ballot - the latter from individuals responding to a campaign advertising the trust as the official charity.
Steve McEwan, the trust's chief executive, said: "Being selected will provide us with a huge fundraising opportunity to support a major new project and increase awareness of our life-saving work."
The new project aims to recruit 13,500 new bone marrow donors aged 18 to 25, from UK universities. Bone marrow from younger donors often produces improved recovery rates for patients after transplants, but it makes up only 6 per cent of the current register.
Help the Hospices, the 2004 official marathon charity, expects to have raised £2m from the association, including pound-for-pound matching from the Tubney Charitable Trust.
As Third Sector went to press, the marathon organisers had not announced the second official charity.