The organisation's Design Review Committee has savaged the £7 million plans for the upgrade of the Chalmers Hospital in the small town of Banff.
MRT's proposals include the retention of a Grade B-listed building on the cottage hospital's site, and the demolition of a series of ancillary buildings dotted around it.
The scheme - for NHS Grampian - also includes the extension and modernisation of the listed building, a proposal that was also slammed by A&DS.
The group's report said: 'The internal alterations to the listed building are not sympathetic to the structure of the building and must, due to the limitations of the built structure, compromise clinical facilities, adjacencies and future flexibility.'
The report also attacks the proposed new-build element of the scheme, which involves knocking down the ancillary buildings.
These replacements, the document says, fail to meet the design standards required to justify the demolition, which falls into a conservation area.
Finally the A&DS report also criticises the layout of the development as 'crammed, with no external space for use by patients and little more than parking between buildings'.