Conde Duque's four exhibition rooms are situated around the South Terrace (lower floor and basement). They can be used independently or as interconnected spaces. During refurbishment, the exhibition space was one of the areas that was most significantly altered; before the renovations in 2005 Conde Duque had 3,012 m² of exhibition space, whereas it currently boasts 5,929 m². All of the rooms on the lower floor can also be opened out onto the South Terrace to further expand their exhibition spaces.
This room runs between Conde Duque Street (calle Conde Duque) and the South Terrace (when facing East to West). It has a basilica-shaped floor plan with three naves that are each 55.3m long, 13m wide and 6m high, with exposed brick walls and granite pillars. Panels have been added between these pillars in order to hang exhibition pieces. The room has an overall useable surface of 645.5m², with 109.9m of panels which are 3.2m high. It has capacity for 215 people.
The second exhibition room lies between the Conde Duque Through-Road (calle Travesía de Conde Duque) and the South Terrace (when facing South to North). It has a layout identical to that of Room 1, but contains additional lateral panelling. The room is 43.8m long, 12.5m wide and 6m high. The overall useable surface is 441 m² and altogether it contains 89.5m of panelling (which is between 3.2m and 5m high). Room 2 has capacity for 150 people.
This room is located between Negras Street (callejón de las Negras) and the South Terrace (when facing West to East). Just like the first two exhibition rooms, the room has a basilica layout, however it contains four naves that are 43m long, 17.3m wide and 6m high. The overall useable surface is 695 m², and it has 117m of panelling, which stands 3.2m high. The room can hold up to 230 people.
The Old Stables. Located below Exhibition Room 3, with direct access to Negras Street (callejón de las Negras). This room is called the ‘Vaulted Room’ because its structure includes five independent vaults. A sixth one is accessed as a partly separated hall and runs parallel to the other vaults and the street. Each vault has slightly different dimensions, but on average they are 15m long, 5.5m wide and 8m tall. The useable surface area of the Vaulted Room is 504 m² and it has capacity for 168 people. These rooms, the old stables of the barracks, are interconnected by a passageway that runs parallel to the street. They are not panelled but, instead, have been left with their original exposed brickwork.