The hospital was founded in 1578 by archbishop Francisco Blanco for the people affected by the terrible plagues that hit the city in the 16th century. The task of designing the building was given to Gaspar de Arce, the person in charge of work on the cathedral of Santiago. The building was finished in 1583. However, it was restored in the second half of the 18th century, and the only remaining trace of the original building is the entrance. It is notable for its austerity and the simplicity of its lines. The facade is built on the lines of a triumphal arch: a semicircular arch is built on thick pilasters and supported by a spring course; this is followed by a load bearing layer, upon which a second body of smaller proportions is built. It is finished with a triangular pediment on slender pilasters which frame two niches with statues of Saint Cosme and Saint Damián, the twin brothers who provided free medical care. An outstanding aspect of the interior is the beautiful and graceful cloister, with four arches on each side supported by Doric columns.
The building currently houses the Padre Sarmiento ((C.S.I.C.), the Secretaria Xeral de Política Lingüística and the Ramón Piñeiro linguistic center