The Willet-Holthuysens retained the 18th-century staircase, and complemented it with 19th-century Deventer stair and corridor runners. These runners were reconstructed using the surviving fragments of the originals in the collection.
The monumental staircase has been at the heart of Herengracht 605 for more than 250 years. Its current appearance dates to the conversion carried out in 1740 by Willem Gideon Deutz, the previous owner of the house. Expensive marble slabs were fitted to the walls and gilded wrought iron banisters installed. Three life-sized white marble statues were commissioned especially for the staircase. The set of sculptures recount the myth of the Judgement of Paris.