The current building was designed by a Portuguese architect in Neo-Manueline style, which evokes Gothic and Renaissance fashions, while The outside is adorned by four statues each depicting an important Portuguese figure - nobleman and military commander who first 'discovered' Brazil, Pablo Alvarez Cabral, the great poet, Luís de Camões, the politician, Infante Dom Henrique de Avis, Duke of Viseu known as Henry the Navigator, and the Portuguese explorer, Vasco de Gama.

grand Chandeliers, ivory, marble and a silver monument adorn the interior of the great Reading Room - during daytime, the atmosphere of the reading room is partiularly unique, as  light comes in through red, white and blue stained-glass windows.

open to the public since 1900, the library receives about one hundred and fifty visitors daily, who come also to see the library's small collection of paintings, sculptures and ancient coins.