The former Hyde Hospital is being offered for sale to residential property developers by the Manchester office of the international real estate advisor.
Tameside Council has already resolved to grant outline planning consent for up to 31 private family homes on 2.73 acres of the 3.84-acre site on Grange Road South.
The sale is being undertaken by Colliers International on behalf of Tameside Hospital NHS Foundation Trust.
The trust had leased the site to Pennine Care for mental health services but patients have since been moved to other locations in Tameside and the buildings are now empty and deemed surplus to the trust's requirements.
Mike Brassington, director of UK development consulting and agency at Colliers International in Manchester, said: "The site of the hospital is in a well established residential area close to Hyde town centre and is potentially an ideal location for traditional private family homes."
Colliers International is selling the site by informal tender and the deadline for submission of tenders is likely to be the end of June.
The value of the site was not disclosed.