Casa Masó is the birthplace of the architect Rafael Masó , a symbol of the development of "Noucentisme" in Girona. Perfectly integrated into the urban environment, the building consists of a ground floor, three apartments and the roof.

The current house is the union of four craftsman-type houses purchased by the Masó family. The façade in Carrer Ballesteries combines the Secessionist style with Barroque-inspired elments. At the rear, glass and ceramic collonades frame the Onyar river.

Rafael Masó made two major alterations to the house. The first, in 1911, when his father commissioned him to adapt the house to the needs of a large and socially ascending family. The second renovation was in 1918, when his brother inherited the house. In addition to unifying the façades, he designed the staircase, the stained glass windows and much of the furniture inside.

For the renovations, the architect turned to the "Modernista" (Catalan Art Nouveau) style prevailing at the time, although he continued to introduce more elements of the nascent "Noucentisme" movement.

Since 2006, this affluent house has been the home of the Rafael Masó Foundation and is currently the only house along the Onyar open to the public.