Cefn Mably Hospital is the name of a hospital which was situated in the St Mellons area of Cardiff, Wales, UK.
A house of some sort stood there in the early 12th century and this was largely rebuilt in the Tudor architecture style in the 16th century; the east wing was subsequently rebuilt from 1688 in Georgian architecture style.
As a manor house, in 1893 it was described by the Cardiff Times as one of the finest and most historic country seats in Wales”. The building was leased by Lord Tredegar at very low cost to the local health authority as a tuberculosis sanatorium in the 1920s. At its opening in 1924 it held 112 patients. Subsequently it became a geriatric hospital.
When it closed down in 1983, the building, which was listed, became derelict. A fire raged through the building in 1994: the remains of the building were eventually converted to luxury apartments.