Sligo County Council has given permission to the HSE North West for a new health care facility at the Nazareth House on Church Hill in Sligo.
The work will include a new three-storey extension to the rear of the existing building, internal refurbishment and installation of a first-floor in a rear hall.
More than 250 car parking spaces are to be provided.
Twenty-two trees will be removed and 78 new trees will be planted.
The Nazareth House itself is a protected structure.
A retirement village is already located on the site at Church Hill.
