The almost mile-long (1 km) hallway at Llandough Hospital, Penarth, was gifted the pictures by the Contemporary Art Society Wales.
They are from the Paintings in Hospitals art collection and intended to make patients feel better.
The display can be used by the region's health and social care organisations.
What is said to be Europe's longest hospital corridor has been adorned with more than 80 paintings, some which have never been seen before.