A Laing O'Rourke team is thought to have won the £60m contract to design and construct a new cancer centre at Guy's Hospital in London.
Kier, Brookfield, Mace, Skanska, and Bovis Lend Lease had also been shortlisted for the scheme.
Laing O'Rourke is partnering with Lord Roger's architects practice, Rogers Stirk Harbour + Partners.
Client is Guy's and St Thomas NHS Foundation Trust.
The 19,000 sq m centre will bring together all the trust's cancer treatment services together in one location.
The scheme is part of the trust's 2020 Vision which proposes a series of other improvement's to the hospital over the next decade.