The last stage in a tour of the Museum, the Sacristy houses two nineteenth-century funerary monuments still dedicated to members of the di Sangro family. Adorning the walls are various marbles dating back to the seventeenth-century decorations of the Sansevero Chapel, as well as large slabs of the original labyrinth flooring.

A display case houses fragments of ancient laboratory tools, belonging perhaps to Raimondo di Sangro himself, discovered during the strengthening and restoration work of the whole monumental complex (1987-1990). Another case houses the reproduction of an eighteenth-century engraving by Giuseppe Aloja, showing the famous sea-going carriage, a strange “device” invented by the Prince of Sansevero.

Since 2005, lastly, this room has also been home to a painting by Giuseppe Pesce, the Madonna and Child, a painting using coloured wax made by Raimondo di Sangro. The Museum Bookshop is also located in the Sacristy.