The Museum has in its keeping a large and steadily growing collection of artefacts. The core of the collections is formed by archaeological objects from surface surveys made within the AZP project during the 1960s and 70s by Stefana Woyda in the western area of Mazovia. There is among them a large group of finds from a few hundred archaeological sites dating to Stone Age through to our the modern age. Over the years the Museum collections were
expanded with finds from archaeological excavations and random discoveries made in the territory of the former Warsaw Voivodeship (from before the 1975 administrative reform). This explains why the Museum collections include archaeological material discovered outside its current area of activity.
The core of the Museum collections are objects recovered during archaeological research carried out by its staff. Particularly valuable is a large group of artefacts from the long-term excavation of ironworking sites dating to the turn of the 1st millennium at Biskupice, Kotowice, Reguły, Milanówek-Falęcin and other locations. This material is now recognized as the Mazovian Centre of Metallurgy active in the region in the late Antiquity.
The most valuable item in the Museum collections is a glass beaker dating to AD 1st-2nd century excavated at Zaborów, decorated with painted depictions of Roman gladiators. Manufactured in Egypt this vessel is the only such find recorded in Europe so far and the pride of the Museum collections.