Addenbrooke's bosses say they could struggle to cope with demand.
Cambridge University Hospitals NHS Foundation Trust said the current funding formula uses old data that doesn't incorporate population growth.
With the government announcing another 150,000 new homes in Cambridge, the Trust said it is concerned the hospital would be overstretched.
The Trust also reiterated the emergency department is already seeing a "huge amount of pressure" with more people attending A&E.
As part of the government's "Case for Cambridge", another £3million has been allocated to the hospital.
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