The Museum is restricted by its trust deed to collecting artefacts from the regular, militia and volunteer infantry units of Berkshire and Wiltshire. It does not contain any items from either county’s Yeomanry units or other military units directly associated with the two counties. The Museum’s collection is wholly owned by its Trust, the Museum is self-funding and non profit making; any money received, usually through donations, goes straight into the running costs of the Museum covering conservation, maintenance and materials etc.

The Museum currently holds over 34,000 items of which approximately 1,200 are on display, with the rest in reserve storage. There are over 16,000 photographs, 6,000 archive documents, 4,000 medals, almost a thousand items of uniform, about 500 weapons, including swords, rifles, pistols, anti-tank weapons, as well as pictures, flags, ornaments and battlefield souvenirs such as a cannon ball from the American War of Independence.