Following major restoration work, which was completed in October 2007,[1] it now houses the museum's study centre (the Escuela del Prado) and library.

Picasso's 1937 Guernica canvas, and the sketches associated with its creation, were displayed at the Casón from 1981, when it was delivered to Spain from New York's Museum of Modern Art (MoMA), to 1992, when it was moved to its current permanent location in a purpose-built gallery at the Museo Nacional Centro de Arte Reina Sofía.

The Casón is located in front of the Puerta de Felipe IV entrance on the west side of Retiro Park.

The artistic importance of Luca Giordano's The Allegory of the Golden Fleece, a c. 1694 fresco on the ceiling of the Casón commissioned by King Charles II of Spain, is one of the possible reasons given for the building having survived when most of the other Bueno Retiro palace complex buildings were demolished in the 19th century.

[2] The library of the Museo del Prado, on the ground floor of the Casón building, consists of the Reading Room for the use of researchers, the museum's technical staff and students of the Escuela del Prado, and the book stores located in the basements.