The troubled Pentland Hill Nursing Home in Edinburgh, which was criticised by the Care Inspectorate, is to be closed by its operator Bupa.
The inspectorate found "serious concerns" during an unannounced inspection last year.
An improvement notice was served on Bupa in January.
The inspectorate said it would work with the City of Edinburgh Council to find new homes for the current residents of Pentland Hill.
Director of inspection Dr Robert Peat said Bupa had been required to make speedy and significant changes.
This involved giving prescribed medicines to residents, providing sufficient food and fluids, training and monitoring staff properly, and following care plans correctly.
But Dr Peat said progress had been "frustratingly slow."
He said: "Every person is entitled to safe, high-quality care.
"We recently reported on some limited improvements at the start of the year, but the pace of change has been frustratingly slow.
"We remain concerned that even where improvements have been made, they may not be sustained.
"Now that Bupa intends to voluntarily close the home, we are working closely with the council to find new homes for the current residents.
"The first priority is the safety and well-being of elderly residents, and we expect all parties to work closely together to minimise the disruption."
Bupa said a shortage of qualified nurses made the closure inevitable.
A spokesman said: "Our residents, their families, and inspectors have recognised the significant improvements made to the home.
"Everyone was committed to investing the resources needed to continue this progress.
"However, recruiting experienced and qualified nurses continues to be a challenge due to the national shortage of nurses and, in particular, in Edinburgh.
"Without more of these nurses it is not possible to take the care home to the level that we want it to reach and maintain this in the long term.
"The home will not be closed until all residents have been found an appropriate new home."