Denbigh Hospital was built in 1844 and closed in 1995
Plans to develop a former psychiatric hospital in Denbigh are "no longer viable" because of the housing market slump, a report has found.
Owners Freemont (Denbigh) Ltd have said they are still keen to develop the site, but must take a "realistic view".
Up to 280 homes, businesses and community facilities were planned for the North Wales Hospital site, which Prince Charles visited in 2004.
Denbighshire Council is talking with the firm to assess "potential options".
The site was sold during a re-organisation of NHS mental health services.
The Lancashire-based developers were given approval for a mixed development of housing, business units and community facilities two years ago.
But they commissioned a financial appraisal which has concluded that "the housing market situation had deteriorated to a point where the scheme was no longer viable in its current form".
The council plans to have more talks with the firm to "address the strategy for the site and potential options."
Freemont consultant Ayub Bhailok said: "It is a setback, but we seem to be heading into difficult times, even a recession, and we've got to take a realistic view.
"It's an uncertain market, but we're still firmly committed to generating capital receipts from the sale of land so that money can be injected back into restoring the listed building."
Mr Bhailok said the company had been forced to review their options and he was unable to say how many new homes would be built.
It wants to develop 17 acres of land for housing and up to 280 homes were suggested when planning permission was granted, despite protests from local campaigners.
Mr Bhailok said talks with consultants and the council are going ahead and some preparation work is taking place.
Welsh historic monuments body Cadw had approved plans for the demolition of some listed buildings and the removal of asbestos from the complex.