Work on a five-storey hospital car park in Derby is due to begin in the spring and be completed by April 2025.
The car park at Royal Derby Hospital, on Uttoxeter Road, will have 875 spaces.
It will be built on the existing Car Park 6, and will provide about 300 additional spaces compared to now.
The University Hospitals of Derby and Burton Trust said it was "one of a number of initiatives we are working on to improve access to our hospitals".
Plans for the car park were approved by Derby City Council last year, and it will mainly be for visitors and patients according to documents sent to the council.
The hospital trust said Car Park 6 will be closed during construction, and it is working to provide alternative parking arrangements for patients during this time.
The Local Democracy Reporting Service said the trust has written to the city council asking to make "minor" changes to the design of the new car park ahead of construction works.
Potential changes include the omission of entrance and exit ramps and to slightly reduce the height of the building "to further minimise the impact... when viewed from Constable Avenue and Owlers Lane".
The council will have to make a decision on the amended plans before construction work can start.
A trust spokesperson said: "We know from feedback from patients and visitors that we could improve their experience by having more available parking spaces at our Royal Derby Hospital site, so we are delighted that plans have been approved for a multi-storey car park with more than 850 spaces, with work beginning in the spring and planned completion for April 2025.
"We appreciate the patience and support of those using the Royal Derby Hospital site while we complete the car parking work and will continue to do all we can to keep disruption to a minimum, and welcome people contacting us if there are any concerns or feedback they would like to share with us."