The militaria department includes a rich collection of white arms - Polish, European and Eastern - dating from the 16th to 19th centuries. The collection includes several hundred pieces, among which two valuable collections stand out in particular: a collection of Polish white arms from the 16th and 17th centuries, donated by Major Witold Buchowski (1896-1976), and a collection of weapons donated by Zygmunt Stanislaw Ipohorski-Lenkiewicz (1903-1997).
 
Major Buchowski's gifts include battle sabers from the 16th and 17th centuries, carbines and an armored cavalry. Some specimens bear the punches of well-known armorers from the second half of the 16th century, including Johannes Wundes of Solingen. Some of the sabers have retained their original scabbards. The collection also includes epaulettes, battle axes, a mace, a hussar's helmet, a capalin, a chapel, a capler and a complete horse row with saddle dating to 1700.
 
The gift of Zygmunt Ipohorski-Lenkiewicz is a valuable addition to the collection. It contains specimens of weapons from Japan (e.g. wakizashi sword), India, Nepal, as well as kris daggers made of Malay damascus, jatagans, kama daggers and tribal weapons from Africa. The collection also includes European swords and rapiers, a hunting knife from 1550, and specimens of Polish sabers used during World War I and World War II until 1976. The donation also included gunpowders, cargo pouches, a caracenoid awl, carvasses and individual pieces of spar weapons: halberd, partisan and sponton.
 
The collection of militaria has also been enriched by weapons purchased by Fr. Jozef Jarzębowski, MIC, including a Polish Tertiary saber, weapons donated by Major Włodzimierz Paczoski and Colonel Antoni Kropielnicki (1905-1992).
 
Also on display in the military section are elements of uniforms: uniforms and field blouses of soldiers of the 2nd Polish Corps, British MK II helmets, military berets belonging to, among others, General Nikodem Sulik and Father Adam Studzinski, the uniform of Lieutenant General Jozef Haller, and the uniform jacket of pilot Zygmunt Zakrzewski (1911-1975) of the 16th Basic Pilotage School in Newton.
 
The collection also includes personal items and military memorabilia: canteens, immortals, bracelets (from 1944-1990), orders and decorations (from 1918-1990), ribbons, patches of the 2nd Polish Corps and a flag from the ship "Silesian".