The two institutions have signed a memorandum of understanding to commit £40 million each to the project, the same amount as founding academic partner University College London.
The other partners in the £700 million project are: the Medical Research Council, which is contributing £300 million; the Wellcome Trust, which will give £120 million; and Cancer Research UK, which is contributing £160 million.
The UKCMRI will accommodate around 1,500 scientists when it opens near St Pancras in London in 2015.
Sir Paul Nurse, director and chief executive of UKCMRI, said the involvement of Imperial and King’s would offer the institute even “greater scale and breadth of knowledge”.
Malcolm Grant, University College London president and provost, said: “Scientific collaboration across a broad base will be essential to the mission and purpose of UKCMRI, and the involvement of other universities is truly welcome. We look forward to developing a strong operational partnership as the underpinning to a truly national institute.”
Sir Keith O’Nions, rector of Imperial College London, said that the UKCMRI had the potential to generate wealth for the UK as well as improvements in health.
“We know that research and innovation contributes hugely to the country’s finances, and in difficult economic times, it is more important than ever that institutions like ours work together to boost the productivity of UK Plc,” he said.