Three days of talks will be held in October, with key players sitting down to discuss what can be done with the Royal Hospital Haslar buildings after it stops being used for medical care.
Sections of the site look set to be used for housing and retail.
The news comes as a blow to campaigners conducting the long-running fight to save Haslar, but they insist the battle is not yet over.
A rough framework for developing the site will be hammered out in the talks and then put out to public consultation later this year.
The meetings are being organised by the Ministry of Defence which owns the land, and will include representatives from Gosport Borough Council and Portsmouth Hospitals NHS Trust.
But the MoD, which is currently allowing the NHS to use Haslar, has not yet confirmed which other organisations will be taking part.
As previously reported in The News, one developer has already put in a bit to build 715 homes on the site, but the Save Haslar Task Force wants to keep housing to a minimum.
Peter Edgar, spokesman for the task force, said: 'The fight isn't over – we've had the same position since the campaign started that we believe the hospital will be needed as part of the hospital system in our area.
'Everybody expected Haslar to be closed in 2001, but it is still open and very busy today.
'There's no reason the part of the site currently used as a hospital can't carry on to be used for medical purposes.
'Ideally, any housing should be for people who work on the site, so they can live there, which will mean there would be no extra congestion on the roads. I just hope common sense prevails.'
An exact date for the talks has not been confirmed, but they are set to take place sometime during October, and the results will be made public over the following weeks.
MoD spokesman Walter Scott said: 'The MoD is not planning on making any specific recommendations.
'It is thought the site will include a mix of different commercial, retail, and health-related industries and some residential areas which could include affordable housing.
'What will come out of this enquiry is a planning brief for the site which will go to public consultation before becoming public policy.'