The new building has 3500 square metres of functional space. Storage space was made in the cellar for the collections of the Department of History and Applied Art, where furniture, metal, weapons, glass and pottery, ecclesiastic and secular textiles, paintings and sculpture, toys, religious objects, medals and orders, and sports found modern equipped spaces with humidity and temperature monitoring and surveillance.
The old building received glass extension spaces with newly equipped restoration workshops of the Conservation and Restoration Department. The administration, curatorial and restoration staff offices of the 2 departments mentioned have remained in the main building of National Museum of Slovenia on Muzejska Street.
The rest of the National Museum of Slovenia - Metelkova premises are exhibition spaces. The first and second floors feature collections for the purpose of studying the history of applied arts with the artefacts dating from the 14th century on. The first floor is reserved for blockbuster exhibitions and public events. In 2009 the second big exhibition was organised with the title Under Napoleon's Eagle – the 200th Anniversary of the Illyrian Provinces in cooperation with the Archives of the Republic of Slovenia (ARS) and the Musée National de l'Armée in Paris.
In 2011 the exhibition European Mannerist Prints in the National Museum of Slovenia featured the highlights from the Slovene national collection, which are mostly printmakers' copies of paintings but include Roman Heroes series by Goltzius or prints by Marcantonio Raimondi.
The Metelkova building enables the museum curators to conceive attractive thematic exhibition such as A Knight, a Lady and a Dragon. The Heritage of Medieval Warriors (2012–2014) or Mummy and the Crocodile: Slovenes Discovering the Lands along the Nile (2014-2015), prepared in collaboration with the Slovene Ethnographic Museum.