Located next to the Plaza of Spain, this building was the former Augustinian convent and later the Senate Building in 1835. From 1931 to 1977 various political events caused the building to be dedicated to other functions. Thus, the republican regime abolished the Senate, and during the reign of Franco the building housed the National Movement until, with the return of democracy, it again became the Senate Building.

The building has undergone many reforms since 1820, the architect Isidro González Velázquez transformed the floor of the church into a chamber and reformed the interior with neoclassical traces. Between 1844 and 1850, Aníbal Álvarez Bouquel carried out a complete restoration of the interior, in addition to building a new neoclassical style façade.

In 1882 it was again modified by Emilio Rodríguez Ayuso, who eliminated all elements of the building that remained of its former religious use and built a magnificent library and reading room. Finally, in 1987 it was decided to expand the complex by adding a new building, which was designed by architect Salvador Gayarre, being inaugurated by King Juan Carlos I in 1991.

Since 2008, the building of the Convento e Iglesia de las Reparadoras has been part of the Senate, which acquired it to expand its facilities and have specific rooms for the self-governing regions, although, as a result of the economic crisis and the lack of budgetary stability, the adaptation work could not be completed. In February 2020, the Senate expansion project was resumed.