St Mary's Hospital is a health facility in Milton Road, Portsmouth, Hampshire, England.

The facility has its origins in the Portsea Island Union Workhouse which was designed by Augustus Livesay and Thomas Ellis Owen and which opened in 1846.

[2] The facility became St Mary's Hospital in 1930 and joined the National Health Service in 1948.

[3] The main block of the old workhouse was converted into flats and re-named "St Mary's House" in 1990.

[4] In May 2018 the trust announced plans to refurbish the buildings and turn the site into a health campus.